April 2025 - Linux-stable-mirror

Re: [PATCH v2] drm/nouveau: Prevent signalled fences in pending list

by Philipp Stanner

On Thu, 2025-04-03 at 15:10 +0200, Christian König wrote: > Am 03.04.25 um 14:58 schrieb Philipp Stanner: > > > > > On Thu, 2025-04-03 at 14:08 +0200, Christian König wrote: > > > > > > > > Am 03.04.25 um 12:13 schrieb Philipp Stanner: > > > > > > > > > > > Nouveau currently relies on the assumption that dma_fences will > > > > only > > > > ever get signalled through nouveau_fence_signal(), which takes > > > > care > > > > of > > > > removing a signalled fence from the list > > > > nouveau_fence_chan.pending. > > > > > > > > This self-imposed rule is violated in nouveau_fence_done(), > > > > where > > > > dma_fence_is_signaled() can signal the fence without removing > > > > it > > > > from > > > > the list. This enables accesses to already signalled fences > > > > through > > > > the > > > > list, which is a bug. > > > > > > > > Furthermore, it must always be possible to use standard > > > > dma_fence > > > > methods an a dma_fence and observe valid behavior. The > > > > canonical > > > > way of > > > > ensuring that signalling a fence has additional effects is to > > > > add > > > > those > > > > effects to a callback and register it on that fence. > > > > > > > > Move the code from nouveau_fence_signal() into a dma_fence > > > > callback. > > > > Register that callback when creating the fence. > > > > > > > > Cc: <stable(a)vger.kernel.org> # 4.10+ > > > > Signed-off-by: Philipp Stanner <phasta(a)kernel.org> > > > > --- > > > > Changes in v2: > > > > - Remove Fixes: tag. (Danilo) > > > > - Remove integer "drop" and call nvif_event_block() in the > > > > fence > > > > callback. (Danilo) > > > > --- > > > > drivers/gpu/drm/nouveau/nouveau_fence.c | 52 +++++++++++++---- > > > > ---- > > > > ---- > > > > drivers/gpu/drm/nouveau/nouveau_fence.h | 1 + > > > > 2 files changed, 29 insertions(+), 24 deletions(-) > > > > > > > > diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c > > > > b/drivers/gpu/drm/nouveau/nouveau_fence.c > > > > index 7cc84472cece..cf510ef9641a 100644 > > > > --- a/drivers/gpu/drm/nouveau/nouveau_fence.c > > > > +++ b/drivers/gpu/drm/nouveau/nouveau_fence.c > > > > @@ -50,24 +50,24 @@ nouveau_fctx(struct nouveau_fence *fence) > > > > return container_of(fence->base.lock, struct > > > > nouveau_fence_chan, lock); > > > > } > > > > > > > > -static int > > > > -nouveau_fence_signal(struct nouveau_fence *fence) > > > > +static void > > > > +nouveau_fence_cleanup_cb(struct dma_fence *dfence, struct > > > > dma_fence_cb *cb) > > > > { > > > > - int drop = 0; > > > > + struct nouveau_fence_chan *fctx; > > > > + struct nouveau_fence *fence; > > > > + > > > > + fence = container_of(dfence, struct nouveau_fence, > > > > base); > > > > + fctx = nouveau_fctx(fence); > > > > > > > > - dma_fence_signal_locked(&fence->base); > > > > list_del(&fence->head); > > > > rcu_assign_pointer(fence->channel, NULL); > > > > > > > > if (test_bit(DMA_FENCE_FLAG_USER_BITS, &fence- > > > > > > > > > > > > > > base.flags)) { > > > > > > > > > > > > > - struct nouveau_fence_chan *fctx = > > > > nouveau_fctx(fence); > > > > - > > > > if (!--fctx->notify_ref) > > > > - drop = 1; > > > > + nvif_event_block(&fctx->event); > > > > } > > > > > > > > dma_fence_put(&fence->base); > > > > - return drop; > > > > } > > > > > > > > static struct nouveau_fence * > > > > @@ -93,8 +93,7 @@ nouveau_fence_context_kill(struct > > > > nouveau_fence_chan *fctx, int error) > > > > if (error) > > > > dma_fence_set_error(&fence->base, > > > > error); > > > > > > > > - if (nouveau_fence_signal(fence)) > > > > - nvif_event_block(&fctx->event); > > > > + dma_fence_signal_locked(&fence->base); > > > > } > > > > fctx->killed = 1; > > > > spin_unlock_irqrestore(&fctx->lock, flags); > > > > @@ -127,11 +126,10 @@ nouveau_fence_context_free(struct > > > > nouveau_fence_chan *fctx) > > > > kref_put(&fctx->fence_ref, nouveau_fence_context_put); > > > > } > > > > > > > > -static int > > > > +static void > > > > nouveau_fence_update(struct nouveau_channel *chan, struct > > > > nouveau_fence_chan *fctx) > > > > { > > > > struct nouveau_fence *fence; > > > > - int drop = 0; > > > > u32 seq = fctx->read(chan); > > > > > > > > while (!list_empty(&fctx->pending)) { > > > > @@ -140,10 +138,8 @@ nouveau_fence_update(struct > > > > nouveau_channel > > > > *chan, struct nouveau_fence_chan *fc > > > > if ((int)(seq - fence->base.seqno) < 0) > > > > break; > > > > > > > > - drop |= nouveau_fence_signal(fence); > > > > + dma_fence_signal_locked(&fence->base); > > > > } > > > > - > > > > - return drop; > > > > } > > > > > > > > static void > > > > @@ -152,7 +148,6 @@ nouveau_fence_uevent_work(struct > > > > work_struct > > > > *work) > > > > struct nouveau_fence_chan *fctx = container_of(work, > > > > struct nouveau_fence_chan, > > > > > > > > uevent_work); > > > > unsigned long flags; > > > > - int drop = 0; > > > > > > > > spin_lock_irqsave(&fctx->lock, flags); > > > > if (!list_empty(&fctx->pending)) { > > > > @@ -161,11 +156,8 @@ nouveau_fence_uevent_work(struct > > > > work_struct > > > > *work) > > > > > > > > fence = list_entry(fctx->pending.next, > > > > typeof(*fence), head); > > > > chan = rcu_dereference_protected(fence- > > > > >channel, > > > > lockdep_is_held(&fctx->lock)); > > > > - if (nouveau_fence_update(chan, fctx)) > > > > - drop = 1; > > > > + nouveau_fence_update(chan, fctx); > > > > } > > > > - if (drop) > > > > - nvif_event_block(&fctx->event); > > > > > > > > spin_unlock_irqrestore(&fctx->lock, flags); > > > > } > > > > @@ -235,6 +227,19 @@ nouveau_fence_emit(struct nouveau_fence > > > > *fence) > > > > &fctx->lock, fctx->context, > > > > ++fctx- > > > > > > > > > > > > > > sequence); > > > > > > > > > > > > > kref_get(&fctx->fence_ref); > > > > > > > > + fence->cb.func = nouveau_fence_cleanup_cb; > > > > + /* Adding a callback runs into > > > > __dma_fence_enable_signaling(), which will > > > > + * ultimately run into nouveau_fence_no_signaling(), > > > > where > > > > a WARN_ON > > > > + * would fire because the refcount can be dropped > > > > there. > > > > + * > > > > + * Increment the refcount here temporarily to work > > > > around > > > > that. > > > > + */ > > > > + dma_fence_get(&fence->base); > > > > + ret = dma_fence_add_callback(&fence->base, &fence->cb, > > > > nouveau_fence_cleanup_cb); > > > > > > > > > > That looks like a really really awkward approach. The driver > > > basically uses a the DMA fence infrastructure as middle layer and > > > callbacks into itself to cleanup it's own structures. > > > > > > > What else are callbacks good for, if not to do something > > automatically > > when the fence gets signaled? > > > > Well if you add a callback for a signal you issued yourself then > that's kind of awkward. > > E.g. you call into the DMA fence code, just for the DMA fence code > to call yourself back again. Now we're entering CS-Philosophy, because it depends on who "you" and "yourself" are. In case of the driver, yes, naturally it registers a callback because at some other place (e.g., in the driver's interrupt handler) the fence will be signaled and the driver wants the callback stuff to be done. If that's not dma_fences' callbacks' purpose, then I'd be interested in knowing what their purpose is, because from my POV this discussion seems to imply that we effectively must never use them for anything. How could it ever be different? Who, for example, registers dma_fence callbacks while not signaling them "himself"? > > > > > > > > > > > Additional to that we don't guarantee any callback order for the > > > DMA > > > fence and so it can be that mix cleaning up the callback with > > > other > > > work which is certainly not good when you want to guarantee that > > > the > > > cleanup happens under the same lock. > > > > > > > Isn't my perception correct that the primary issue you have with > > this > > approach is that dma_fence_put() is called from within the > > callback? Or > > do you also take issue with deleting from the list? > > > > Well kind of both. The issue is that the caller of > dma_fence_signal() or dma_fence_signal_locked() must hold the > reference until the function returns. > > When you do the list cleanup and the drop inside the callback it is > perfectly possible that the fence pointer becomes stale before you > return and that's really not a good idea. In other words, you would prefer if this patch would have a function with my callback's code in a function, and that function would be called at every place where the driver signals a fence? If that's your opinion, then, IOW, it would mean for us to go almost back to status quo, with nouveau_fence_signal2.0, but with the dma_fence_is_signaled() part fixed. P. > > > > > > > > > > > > > > Instead the call to dma_fence_signal_locked() should probably be > > > removed from nouveau_fence_signal() and into > > > nouveau_fence_context_kill() and nouveau_fence_update(). > > > > > > This way nouveau_fence_is_signaled() can call this function as > > > well. > > > > > > > Which "this function"? dma_fence_signal_locked() > > > > No the cleanup function for the list entry. Whatever you call that > then, the name nouveau_fence_signal() is probably not appropriate any > more. > > > > > > > > > > > > > > BTW: nouveau_fence_no_signaling() looks completely broken as > > > well. It > > > calls nouveau_fence_is_signaled() and then list_del() on the > > > fence > > > head. > > > > > > > I can assure you that a great many things in Nouveau look > > completely > > broken. > > > > The question for us is always the cost-benefit-ratio when fixing > > bugs. > > There are fixes that solve the bug with reasonable effort, and > > there > > are great reworks towards an ideal state. > > > > I would just simply drop that function. As far as I can see it > severs no purpose other than doing exactly what the common DMA fence > code does anyway. > > Just one less thing which could fail. > > Christian. > > > > > > > > P. > > > > > > > > > > > > As far as I can see that is completely superfluous and should > > > probably be dropped. IIRC I once had a patch to clean that up but > > > it > > > was dropped for some reason. > > > > > > Regards, > > > Christian. > > > > > > > > > > > > > > > > > + dma_fence_put(&fence->base); > > > > + if (ret) > > > > + return ret; > > > > + > > > > ret = fctx->emit(fence); > > > > if (!ret) { > > > > dma_fence_get(&fence->base); > > > > @@ -246,8 +251,7 @@ nouveau_fence_emit(struct nouveau_fence > > > > *fence) > > > > return -ENODEV; > > > > } > > > > > > > > - if (nouveau_fence_update(chan, fctx)) > > > > - nvif_event_block(&fctx->event); > > > > + nouveau_fence_update(chan, fctx); > > > > > > > > list_add_tail(&fence->head, &fctx->pending); > > > > spin_unlock_irq(&fctx->lock); > > > > @@ -270,8 +274,8 @@ nouveau_fence_done(struct nouveau_fence > > > > *fence) > > > > > > > > spin_lock_irqsave(&fctx->lock, flags); > > > > chan = rcu_dereference_protected(fence- > > > > >channel, > > > > lockdep_is_held(&fctx->lock)); > > > > - if (chan && nouveau_fence_update(chan, fctx)) > > > > - nvif_event_block(&fctx->event); > > > > + if (chan) > > > > + nouveau_fence_update(chan, fctx); > > > > spin_unlock_irqrestore(&fctx->lock, flags); > > > > } > > > > return dma_fence_is_signaled(&fence->base); > > > > diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.h > > > > b/drivers/gpu/drm/nouveau/nouveau_fence.h > > > > index 8bc065acfe35..e6b2df7fdc42 100644 > > > > --- a/drivers/gpu/drm/nouveau/nouveau_fence.h > > > > +++ b/drivers/gpu/drm/nouveau/nouveau_fence.h > > > > @@ -10,6 +10,7 @@ struct nouveau_bo; > > > > > > > > struct nouveau_fence { > > > > struct dma_fence base; > > > > + struct dma_fence_cb cb; > > > > > > > > struct list_head head; > > > > > > > > > > > > > > >

2 months, 1 week

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FAILED: patch "[PATCH] tty: serial: lpuart: only disable CTS instead of overwriting" failed to apply to 6.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.14.y git checkout FETCH_HEAD git cherry-pick -x e98ab45ec5182605d2e00114cba3bbf46b0ea27f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025040353-panda-varnish-c8a4@gregkh' --subject-prefix 'PATCH 6.14.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From e98ab45ec5182605d2e00114cba3bbf46b0ea27f Mon Sep 17 00:00:00 2001 From: Sherry Sun <sherry.sun(a)nxp.com> Date: Fri, 7 Mar 2025 14:54:46 +0800 Subject: [PATCH] tty: serial: lpuart: only disable CTS instead of overwriting the whole UARTMODIR register No need to overwrite the whole UARTMODIR register before waiting the transmit engine complete, actually our target here is only to disable CTS flow control to avoid the dirty data in TX FIFO may block the transmit engine complete. Also delete the following duplicate CTS disable configuration. Fixes: d5a2e0834364 ("tty: serial: lpuart: disable flow control while waiting for the transmit engine to complete") Cc: stable <stable(a)kernel.org> Signed-off-by: Sherry Sun <sherry.sun(a)nxp.com> Link: https://lore.kernel.org/r/20250307065446.1122482-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index c8cc0a241fba..33eeefa6fa8f 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -2349,15 +2349,19 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, /* update the per-port timeout */ uart_update_timeout(port, termios->c_cflag, baud); + /* + * disable CTS to ensure the transmit engine is not blocked by the flow + * control when there is dirty data in TX FIFO + */ + lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); + /* * LPUART Transmission Complete Flag may never be set while queuing a break * character, so skip waiting for transmission complete when UARTCTRL_SBK is * asserted. */ - if (!(old_ctrl & UARTCTRL_SBK)) { - lpuart32_write(port, 0, UARTMODIR); + if (!(old_ctrl & UARTCTRL_SBK)) lpuart32_wait_bit_set(port, UARTSTAT, UARTSTAT_TC); - } /* disable transmit and receive */ lpuart32_write(port, old_ctrl & ~(UARTCTRL_TE | UARTCTRL_RE), @@ -2365,8 +2369,6 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, lpuart32_write(port, bd, UARTBAUD); lpuart32_serial_setbrg(sport, baud); - /* disable CTS before enabling UARTCTRL_TE to avoid pending idle preamble */ - lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); /* restore control register */ lpuart32_write(port, ctrl, UARTCTRL); /* re-enable the CTS if needed */

2 months, 1 week

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FAILED: patch "[PATCH] tty: serial: lpuart: only disable CTS instead of overwriting" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x e98ab45ec5182605d2e00114cba3bbf46b0ea27f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025040352-shortwave-groom-7165@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From e98ab45ec5182605d2e00114cba3bbf46b0ea27f Mon Sep 17 00:00:00 2001 From: Sherry Sun <sherry.sun(a)nxp.com> Date: Fri, 7 Mar 2025 14:54:46 +0800 Subject: [PATCH] tty: serial: lpuart: only disable CTS instead of overwriting the whole UARTMODIR register No need to overwrite the whole UARTMODIR register before waiting the transmit engine complete, actually our target here is only to disable CTS flow control to avoid the dirty data in TX FIFO may block the transmit engine complete. Also delete the following duplicate CTS disable configuration. Fixes: d5a2e0834364 ("tty: serial: lpuart: disable flow control while waiting for the transmit engine to complete") Cc: stable <stable(a)kernel.org> Signed-off-by: Sherry Sun <sherry.sun(a)nxp.com> Link: https://lore.kernel.org/r/20250307065446.1122482-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index c8cc0a241fba..33eeefa6fa8f 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -2349,15 +2349,19 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, /* update the per-port timeout */ uart_update_timeout(port, termios->c_cflag, baud); + /* + * disable CTS to ensure the transmit engine is not blocked by the flow + * control when there is dirty data in TX FIFO + */ + lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); + /* * LPUART Transmission Complete Flag may never be set while queuing a break * character, so skip waiting for transmission complete when UARTCTRL_SBK is * asserted. */ - if (!(old_ctrl & UARTCTRL_SBK)) { - lpuart32_write(port, 0, UARTMODIR); + if (!(old_ctrl & UARTCTRL_SBK)) lpuart32_wait_bit_set(port, UARTSTAT, UARTSTAT_TC); - } /* disable transmit and receive */ lpuart32_write(port, old_ctrl & ~(UARTCTRL_TE | UARTCTRL_RE), @@ -2365,8 +2369,6 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, lpuart32_write(port, bd, UARTBAUD); lpuart32_serial_setbrg(sport, baud); - /* disable CTS before enabling UARTCTRL_TE to avoid pending idle preamble */ - lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); /* restore control register */ lpuart32_write(port, ctrl, UARTCTRL); /* re-enable the CTS if needed */

2 months, 1 week

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FAILED: patch "[PATCH] tty: serial: lpuart: only disable CTS instead of overwriting" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x e98ab45ec5182605d2e00114cba3bbf46b0ea27f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025040352-makeover-hardening-da0e@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From e98ab45ec5182605d2e00114cba3bbf46b0ea27f Mon Sep 17 00:00:00 2001 From: Sherry Sun <sherry.sun(a)nxp.com> Date: Fri, 7 Mar 2025 14:54:46 +0800 Subject: [PATCH] tty: serial: lpuart: only disable CTS instead of overwriting the whole UARTMODIR register No need to overwrite the whole UARTMODIR register before waiting the transmit engine complete, actually our target here is only to disable CTS flow control to avoid the dirty data in TX FIFO may block the transmit engine complete. Also delete the following duplicate CTS disable configuration. Fixes: d5a2e0834364 ("tty: serial: lpuart: disable flow control while waiting for the transmit engine to complete") Cc: stable <stable(a)kernel.org> Signed-off-by: Sherry Sun <sherry.sun(a)nxp.com> Link: https://lore.kernel.org/r/20250307065446.1122482-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index c8cc0a241fba..33eeefa6fa8f 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -2349,15 +2349,19 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, /* update the per-port timeout */ uart_update_timeout(port, termios->c_cflag, baud); + /* + * disable CTS to ensure the transmit engine is not blocked by the flow + * control when there is dirty data in TX FIFO + */ + lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); + /* * LPUART Transmission Complete Flag may never be set while queuing a break * character, so skip waiting for transmission complete when UARTCTRL_SBK is * asserted. */ - if (!(old_ctrl & UARTCTRL_SBK)) { - lpuart32_write(port, 0, UARTMODIR); + if (!(old_ctrl & UARTCTRL_SBK)) lpuart32_wait_bit_set(port, UARTSTAT, UARTSTAT_TC); - } /* disable transmit and receive */ lpuart32_write(port, old_ctrl & ~(UARTCTRL_TE | UARTCTRL_RE), @@ -2365,8 +2369,6 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, lpuart32_write(port, bd, UARTBAUD); lpuart32_serial_setbrg(sport, baud); - /* disable CTS before enabling UARTCTRL_TE to avoid pending idle preamble */ - lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); /* restore control register */ lpuart32_write(port, ctrl, UARTCTRL); /* re-enable the CTS if needed */

2 months, 1 week

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FAILED: patch "[PATCH] tty: serial: lpuart: only disable CTS instead of overwriting" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x e98ab45ec5182605d2e00114cba3bbf46b0ea27f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025040351-unbalance-hypocrite-ec8a@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From e98ab45ec5182605d2e00114cba3bbf46b0ea27f Mon Sep 17 00:00:00 2001 From: Sherry Sun <sherry.sun(a)nxp.com> Date: Fri, 7 Mar 2025 14:54:46 +0800 Subject: [PATCH] tty: serial: lpuart: only disable CTS instead of overwriting the whole UARTMODIR register No need to overwrite the whole UARTMODIR register before waiting the transmit engine complete, actually our target here is only to disable CTS flow control to avoid the dirty data in TX FIFO may block the transmit engine complete. Also delete the following duplicate CTS disable configuration. Fixes: d5a2e0834364 ("tty: serial: lpuart: disable flow control while waiting for the transmit engine to complete") Cc: stable <stable(a)kernel.org> Signed-off-by: Sherry Sun <sherry.sun(a)nxp.com> Link: https://lore.kernel.org/r/20250307065446.1122482-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index c8cc0a241fba..33eeefa6fa8f 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -2349,15 +2349,19 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, /* update the per-port timeout */ uart_update_timeout(port, termios->c_cflag, baud); + /* + * disable CTS to ensure the transmit engine is not blocked by the flow + * control when there is dirty data in TX FIFO + */ + lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); + /* * LPUART Transmission Complete Flag may never be set while queuing a break * character, so skip waiting for transmission complete when UARTCTRL_SBK is * asserted. */ - if (!(old_ctrl & UARTCTRL_SBK)) { - lpuart32_write(port, 0, UARTMODIR); + if (!(old_ctrl & UARTCTRL_SBK)) lpuart32_wait_bit_set(port, UARTSTAT, UARTSTAT_TC); - } /* disable transmit and receive */ lpuart32_write(port, old_ctrl & ~(UARTCTRL_TE | UARTCTRL_RE), @@ -2365,8 +2369,6 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, lpuart32_write(port, bd, UARTBAUD); lpuart32_serial_setbrg(sport, baud); - /* disable CTS before enabling UARTCTRL_TE to avoid pending idle preamble */ - lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); /* restore control register */ lpuart32_write(port, ctrl, UARTCTRL); /* re-enable the CTS if needed */

2 months, 1 week

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FAILED: patch "[PATCH] tty: serial: lpuart: only disable CTS instead of overwriting" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x e98ab45ec5182605d2e00114cba3bbf46b0ea27f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025040351-clay-riches-1f07@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From e98ab45ec5182605d2e00114cba3bbf46b0ea27f Mon Sep 17 00:00:00 2001 From: Sherry Sun <sherry.sun(a)nxp.com> Date: Fri, 7 Mar 2025 14:54:46 +0800 Subject: [PATCH] tty: serial: lpuart: only disable CTS instead of overwriting the whole UARTMODIR register No need to overwrite the whole UARTMODIR register before waiting the transmit engine complete, actually our target here is only to disable CTS flow control to avoid the dirty data in TX FIFO may block the transmit engine complete. Also delete the following duplicate CTS disable configuration. Fixes: d5a2e0834364 ("tty: serial: lpuart: disable flow control while waiting for the transmit engine to complete") Cc: stable <stable(a)kernel.org> Signed-off-by: Sherry Sun <sherry.sun(a)nxp.com> Link: https://lore.kernel.org/r/20250307065446.1122482-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index c8cc0a241fba..33eeefa6fa8f 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -2349,15 +2349,19 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, /* update the per-port timeout */ uart_update_timeout(port, termios->c_cflag, baud); + /* + * disable CTS to ensure the transmit engine is not blocked by the flow + * control when there is dirty data in TX FIFO + */ + lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); + /* * LPUART Transmission Complete Flag may never be set while queuing a break * character, so skip waiting for transmission complete when UARTCTRL_SBK is * asserted. */ - if (!(old_ctrl & UARTCTRL_SBK)) { - lpuart32_write(port, 0, UARTMODIR); + if (!(old_ctrl & UARTCTRL_SBK)) lpuart32_wait_bit_set(port, UARTSTAT, UARTSTAT_TC); - } /* disable transmit and receive */ lpuart32_write(port, old_ctrl & ~(UARTCTRL_TE | UARTCTRL_RE), @@ -2365,8 +2369,6 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, lpuart32_write(port, bd, UARTBAUD); lpuart32_serial_setbrg(sport, baud); - /* disable CTS before enabling UARTCTRL_TE to avoid pending idle preamble */ - lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); /* restore control register */ lpuart32_write(port, ctrl, UARTCTRL); /* re-enable the CTS if needed */

2 months, 1 week

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FAILED: patch "[PATCH] tty: serial: lpuart: only disable CTS instead of overwriting" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x e98ab45ec5182605d2e00114cba3bbf46b0ea27f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025040350-genre-establish-976c@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From e98ab45ec5182605d2e00114cba3bbf46b0ea27f Mon Sep 17 00:00:00 2001 From: Sherry Sun <sherry.sun(a)nxp.com> Date: Fri, 7 Mar 2025 14:54:46 +0800 Subject: [PATCH] tty: serial: lpuart: only disable CTS instead of overwriting the whole UARTMODIR register No need to overwrite the whole UARTMODIR register before waiting the transmit engine complete, actually our target here is only to disable CTS flow control to avoid the dirty data in TX FIFO may block the transmit engine complete. Also delete the following duplicate CTS disable configuration. Fixes: d5a2e0834364 ("tty: serial: lpuart: disable flow control while waiting for the transmit engine to complete") Cc: stable <stable(a)kernel.org> Signed-off-by: Sherry Sun <sherry.sun(a)nxp.com> Link: https://lore.kernel.org/r/20250307065446.1122482-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index c8cc0a241fba..33eeefa6fa8f 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -2349,15 +2349,19 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, /* update the per-port timeout */ uart_update_timeout(port, termios->c_cflag, baud); + /* + * disable CTS to ensure the transmit engine is not blocked by the flow + * control when there is dirty data in TX FIFO + */ + lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); + /* * LPUART Transmission Complete Flag may never be set while queuing a break * character, so skip waiting for transmission complete when UARTCTRL_SBK is * asserted. */ - if (!(old_ctrl & UARTCTRL_SBK)) { - lpuart32_write(port, 0, UARTMODIR); + if (!(old_ctrl & UARTCTRL_SBK)) lpuart32_wait_bit_set(port, UARTSTAT, UARTSTAT_TC); - } /* disable transmit and receive */ lpuart32_write(port, old_ctrl & ~(UARTCTRL_TE | UARTCTRL_RE), @@ -2365,8 +2369,6 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, lpuart32_write(port, bd, UARTBAUD); lpuart32_serial_setbrg(sport, baud); - /* disable CTS before enabling UARTCTRL_TE to avoid pending idle preamble */ - lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); /* restore control register */ lpuart32_write(port, ctrl, UARTCTRL); /* re-enable the CTS if needed */

2 months, 1 week

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FAILED: patch "[PATCH] tty: serial: lpuart: only disable CTS instead of overwriting" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x e98ab45ec5182605d2e00114cba3bbf46b0ea27f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025040350-outpour-uplifting-c895@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From e98ab45ec5182605d2e00114cba3bbf46b0ea27f Mon Sep 17 00:00:00 2001 From: Sherry Sun <sherry.sun(a)nxp.com> Date: Fri, 7 Mar 2025 14:54:46 +0800 Subject: [PATCH] tty: serial: lpuart: only disable CTS instead of overwriting the whole UARTMODIR register No need to overwrite the whole UARTMODIR register before waiting the transmit engine complete, actually our target here is only to disable CTS flow control to avoid the dirty data in TX FIFO may block the transmit engine complete. Also delete the following duplicate CTS disable configuration. Fixes: d5a2e0834364 ("tty: serial: lpuart: disable flow control while waiting for the transmit engine to complete") Cc: stable <stable(a)kernel.org> Signed-off-by: Sherry Sun <sherry.sun(a)nxp.com> Link: https://lore.kernel.org/r/20250307065446.1122482-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index c8cc0a241fba..33eeefa6fa8f 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -2349,15 +2349,19 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, /* update the per-port timeout */ uart_update_timeout(port, termios->c_cflag, baud); + /* + * disable CTS to ensure the transmit engine is not blocked by the flow + * control when there is dirty data in TX FIFO + */ + lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); + /* * LPUART Transmission Complete Flag may never be set while queuing a break * character, so skip waiting for transmission complete when UARTCTRL_SBK is * asserted. */ - if (!(old_ctrl & UARTCTRL_SBK)) { - lpuart32_write(port, 0, UARTMODIR); + if (!(old_ctrl & UARTCTRL_SBK)) lpuart32_wait_bit_set(port, UARTSTAT, UARTSTAT_TC); - } /* disable transmit and receive */ lpuart32_write(port, old_ctrl & ~(UARTCTRL_TE | UARTCTRL_RE), @@ -2365,8 +2369,6 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, lpuart32_write(port, bd, UARTBAUD); lpuart32_serial_setbrg(sport, baud); - /* disable CTS before enabling UARTCTRL_TE to avoid pending idle preamble */ - lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); /* restore control register */ lpuart32_write(port, ctrl, UARTCTRL); /* re-enable the CTS if needed */

2 months, 1 week

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FAILED: patch "[PATCH] tty: serial: lpuart: only disable CTS instead of overwriting" failed to apply to 6.13-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.13-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.13.y git checkout FETCH_HEAD git cherry-pick -x e98ab45ec5182605d2e00114cba3bbf46b0ea27f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025040349-defrost-doubling-19f6@gregkh' --subject-prefix 'PATCH 6.13.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From e98ab45ec5182605d2e00114cba3bbf46b0ea27f Mon Sep 17 00:00:00 2001 From: Sherry Sun <sherry.sun(a)nxp.com> Date: Fri, 7 Mar 2025 14:54:46 +0800 Subject: [PATCH] tty: serial: lpuart: only disable CTS instead of overwriting the whole UARTMODIR register No need to overwrite the whole UARTMODIR register before waiting the transmit engine complete, actually our target here is only to disable CTS flow control to avoid the dirty data in TX FIFO may block the transmit engine complete. Also delete the following duplicate CTS disable configuration. Fixes: d5a2e0834364 ("tty: serial: lpuart: disable flow control while waiting for the transmit engine to complete") Cc: stable <stable(a)kernel.org> Signed-off-by: Sherry Sun <sherry.sun(a)nxp.com> Link: https://lore.kernel.org/r/20250307065446.1122482-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index c8cc0a241fba..33eeefa6fa8f 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -2349,15 +2349,19 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, /* update the per-port timeout */ uart_update_timeout(port, termios->c_cflag, baud); + /* + * disable CTS to ensure the transmit engine is not blocked by the flow + * control when there is dirty data in TX FIFO + */ + lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); + /* * LPUART Transmission Complete Flag may never be set while queuing a break * character, so skip waiting for transmission complete when UARTCTRL_SBK is * asserted. */ - if (!(old_ctrl & UARTCTRL_SBK)) { - lpuart32_write(port, 0, UARTMODIR); + if (!(old_ctrl & UARTCTRL_SBK)) lpuart32_wait_bit_set(port, UARTSTAT, UARTSTAT_TC); - } /* disable transmit and receive */ lpuart32_write(port, old_ctrl & ~(UARTCTRL_TE | UARTCTRL_RE), @@ -2365,8 +2369,6 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios, lpuart32_write(port, bd, UARTBAUD); lpuart32_serial_setbrg(sport, baud); - /* disable CTS before enabling UARTCTRL_TE to avoid pending idle preamble */ - lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR); /* restore control register */ lpuart32_write(port, ctrl, UARTCTRL); /* re-enable the CTS if needed */

2 months, 1 week

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FAILED: patch "[PATCH] tty: serial: fsl_lpuart: disable transmitter before changing" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x f5cb528d6441eb860250a2f085773aac4f44085e # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025040331-baking-headgear-81e4@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From f5cb528d6441eb860250a2f085773aac4f44085e Mon Sep 17 00:00:00 2001 From: Sherry Sun <sherry.sun(a)nxp.com> Date: Wed, 12 Mar 2025 10:25:03 +0800 Subject: [PATCH] tty: serial: fsl_lpuart: disable transmitter before changing RS485 related registers According to the LPUART reference manual, TXRTSE and TXRTSPOL of MODIR register only can be changed when the transmitter is disabled. So disable the transmitter before changing RS485 related registers and re-enable it after the change is done. Fixes: 67b01837861c ("tty: serial: lpuart: Add RS485 support for 32-bit uart flavour") Cc: stable <stable(a)kernel.org> Signed-off-by: Sherry Sun <sherry.sun(a)nxp.com> Reviewed-by: Frank Li <Frank.Li(a)nxp.com> Link: https://lore.kernel.org/r/20250312022503.1342990-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index 91d02c55c470..203ec3b46304 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -1484,6 +1484,19 @@ static int lpuart32_config_rs485(struct uart_port *port, struct ktermios *termio unsigned long modem = lpuart32_read(&sport->port, UARTMODIR) & ~(UARTMODIR_TXRTSPOL | UARTMODIR_TXRTSE); + u32 ctrl; + + /* TXRTSE and TXRTSPOL only can be changed when transmitter is disabled. */ + ctrl = lpuart32_read(&sport->port, UARTCTRL); + if (ctrl & UARTCTRL_TE) { + /* wait for the transmit engine to complete */ + lpuart32_wait_bit_set(&sport->port, UARTSTAT, UARTSTAT_TC); + lpuart32_write(&sport->port, ctrl & ~UARTCTRL_TE, UARTCTRL); + + while (lpuart32_read(&sport->port, UARTCTRL) & UARTCTRL_TE) + cpu_relax(); + } + lpuart32_write(&sport->port, modem, UARTMODIR); if (rs485->flags & SER_RS485_ENABLED) { @@ -1503,6 +1516,10 @@ static int lpuart32_config_rs485(struct uart_port *port, struct ktermios *termio } lpuart32_write(&sport->port, modem, UARTMODIR); + + if (ctrl & UARTCTRL_TE) + lpuart32_write(&sport->port, ctrl, UARTCTRL); + return 0; }

2 months, 1 week

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