This is a note to let you know that I've just added the patch titled

USB: xhci: fix U1/U2 handling for hardware with XHCI_INTEL_HOST quirk

to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 5d5323a6f3625f101dbfa94ba3ef7706cce38760 Mon Sep 17 00:00:00 2001

From: Michael Grzeschik m.grzeschik@pengutronix.de Date: Tue, 15 Dec 2020 20:31:47 +0100 Subject: USB: xhci: fix U1/U2 handling for hardware with XHCI_INTEL_HOST quirk set

The commit 0472bf06c6fd ("xhci: Prevent U1/U2 link pm states if exit latency is too long") was constraining the xhci code not to allow U1/U2 sleep states if the latency to wake up from the U-states reached the service interval of an periodic endpoint. This fix was not taking into account that in case the quirk XHCI_INTEL_HOST is set, the wakeup time will be calculated and configured differently.

It checks for u1_params.mel/u2_params.mel as a limit. But the code could decide to write another MEL into the hardware. This leads to broken cases where not enough bandwidth is available for other devices:

usb 1-2: can't set config #1, error -28

This patch is fixing that case by checking for timeout_ns after the wakeup time was calculated depending on the quirks.

Fixes: 0472bf06c6fd ("xhci: Prevent U1/U2 link pm states if exit latency is too long") Signed-off-by: Michael Grzeschik m.grzeschik@pengutronix.de Cc: stable stable@vger.kernel.org Link: https://lore.kernel.org/r/20201215193147.11738-1-m.grzeschik@pengutronix.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/host/xhci.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 91ab81c3fc79..e86940571b4c 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -4770,19 +4770,19 @@ static u16 xhci_calculate_u1_timeout(struct xhci_hcd *xhci, { unsigned long long timeout_ns;

+ if (xhci->quirks & XHCI_INTEL_HOST) + timeout_ns = xhci_calculate_intel_u1_timeout(udev, desc); + else + timeout_ns = udev->u1_params.sel; + /* Prevent U1 if service interval is shorter than U1 exit latency */ if (usb_endpoint_xfer_int(desc) || usb_endpoint_xfer_isoc(desc)) { - if (xhci_service_interval_to_ns(desc) <= udev->u1_params.mel) { + if (xhci_service_interval_to_ns(desc) <= timeout_ns) { dev_dbg(&udev->dev, "Disable U1, ESIT shorter than exit latency\n"); return USB3_LPM_DISABLED; } }

- if (xhci->quirks & XHCI_INTEL_HOST) - timeout_ns = xhci_calculate_intel_u1_timeout(udev, desc); - else - timeout_ns = udev->u1_params.sel; - /* The U1 timeout is encoded in 1us intervals. * Don't return a timeout of zero, because that's USB3_LPM_DISABLED. */ @@ -4834,19 +4834,19 @@ static u16 xhci_calculate_u2_timeout(struct xhci_hcd *xhci, { unsigned long long timeout_ns;

+ if (xhci->quirks & XHCI_INTEL_HOST) + timeout_ns = xhci_calculate_intel_u2_timeout(udev, desc); + else + timeout_ns = udev->u2_params.sel; + /* Prevent U2 if service interval is shorter than U2 exit latency */ if (usb_endpoint_xfer_int(desc) || usb_endpoint_xfer_isoc(desc)) { - if (xhci_service_interval_to_ns(desc) <= udev->u2_params.mel) { + if (xhci_service_interval_to_ns(desc) <= timeout_ns) { dev_dbg(&udev->dev, "Disable U2, ESIT shorter than exit latency\n"); return USB3_LPM_DISABLED; } }

- if (xhci->quirks & XHCI_INTEL_HOST) - timeout_ns = xhci_calculate_intel_u2_timeout(udev, desc); - else - timeout_ns = udev->u2_params.sel; - /* The U2 timeout is encoded in 256us intervals */ timeout_ns = DIV_ROUND_UP_ULL(timeout_ns, 256 * 1000); /* If the necessary timeout value is bigger than what we can set in the