This is a note to let you know that I've just added the patch titled
ext4: correct documentation for grpid mount option
to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
ext4-correct-documentation-for-grpid-mount-option.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
>From 9f0372488cc9243018a812e8cfbf27de650b187b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ernesto=20A=2E=20Fern=C3=A1ndez?=
<ernesto.mnd.fernandez(a)gmail.com>
Date: Thu, 11 Jan 2018 13:43:33 -0500
Subject: ext4: correct documentation for grpid mount option
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
From: Ernesto A. Fernández <ernesto.mnd.fernandez(a)gmail.com>
commit 9f0372488cc9243018a812e8cfbf27de650b187b upstream.
The grpid option is currently described as being the same as nogrpid.
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez(a)gmail.com>
Signed-off-by: Theodore Ts'o <tytso(a)mit.edu>
Cc: stable(a)vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
Documentation/filesystems/ext4.txt | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -233,7 +233,7 @@ data_err=ignore(*) Just print an error m
data_err=abort Abort the journal if an error occurs in a file
data buffer in ordered mode.
-grpid Give objects the same group ID as their creator.
+grpid New objects have the group ID of their parent.
bsdgroups
nogrpid (*) New objects have the group ID of their creator.
Patches currently in stable-queue which might be from ernesto.mnd.fernandez(a)gmail.com are
queue-3.18/ext4-correct-documentation-for-grpid-mount-option.patch
This is a note to let you know that I've just added the patch titled
console/dummy: leave .con_font_get set to NULL
to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
console-dummy-leave-.con_font_get-set-to-null.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
>From 724ba8b30b044aa0d94b1cd374fc15806cdd6f18 Mon Sep 17 00:00:00 2001
From: Nicolas Pitre <nicolas.pitre(a)linaro.org>
Date: Mon, 15 Jan 2018 17:04:22 +0100
Subject: console/dummy: leave .con_font_get set to NULL
From: Nicolas Pitre <nicolas.pitre(a)linaro.org>
commit 724ba8b30b044aa0d94b1cd374fc15806cdd6f18 upstream.
When this method is set, the caller expects struct console_font fields
to be properly initialized when it returns. Leave it unset otherwise
nonsensical (leaked kernel stack) values are returned to user space.
Signed-off-by: Nicolas Pitre <nico(a)linaro.org>
Cc: stable(a)vger.kernel.org
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie(a)samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
drivers/video/console/dummycon.c | 1 -
1 file changed, 1 deletion(-)
--- a/drivers/video/console/dummycon.c
+++ b/drivers/video/console/dummycon.c
@@ -71,7 +71,6 @@ const struct consw dummy_con = {
.con_switch = DUMMY,
.con_blank = DUMMY,
.con_font_set = DUMMY,
- .con_font_get = DUMMY,
.con_font_default = DUMMY,
.con_font_copy = DUMMY,
.con_set_palette = DUMMY,
Patches currently in stable-queue which might be from nicolas.pitre(a)linaro.org are
queue-3.18/console-dummy-leave-.con_font_get-set-to-null.patch
The patch below does not apply to the 4.9-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 77dd66a3c67c93ab401ccc15efff25578be281fd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20H=2E=20Sch=C3=B6nherr?= <jschoenh(a)amazon.de>
Date: Fri, 19 Jan 2018 16:26:33 -0800
Subject: [PATCH] mm: Fix devm_memremap_pages() collision handling
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
If devm_memremap_pages() detects a collision while adding entries
to the radix-tree, we call pgmap_radix_release(). Unfortunately,
the function removes *all* entries for the range -- including the
entries that caused the collision in the first place.
Modify pgmap_radix_release() to take an additional argument to
indicate where to stop, so that only newly added entries are removed
from the tree.
Cc: <stable(a)vger.kernel.org>
Fixes: 9476df7d80df ("mm: introduce find_dev_pagemap()")
Signed-off-by: Jan H. Schönherr <jschoenh(a)amazon.de>
Signed-off-by: Dan Williams <dan.j.williams(a)intel.com>
diff --git a/kernel/memremap.c b/kernel/memremap.c
index 4ef97525a4ff..4849be5f9b3c 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -241,13 +241,16 @@ int device_private_entry_fault(struct vm_area_struct *vma,
EXPORT_SYMBOL(device_private_entry_fault);
#endif /* CONFIG_DEVICE_PRIVATE */
-static void pgmap_radix_release(struct resource *res)
+static void pgmap_radix_release(struct resource *res, unsigned long end_pgoff)
{
unsigned long pgoff, order;
mutex_lock(&pgmap_lock);
- foreach_order_pgoff(res, order, pgoff)
+ foreach_order_pgoff(res, order, pgoff) {
+ if (pgoff >= end_pgoff)
+ break;
radix_tree_delete(&pgmap_radix, PHYS_PFN(res->start) + pgoff);
+ }
mutex_unlock(&pgmap_lock);
synchronize_rcu();
@@ -302,7 +305,7 @@ static void devm_memremap_pages_release(void *data)
mem_hotplug_done();
untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
- pgmap_radix_release(res);
+ pgmap_radix_release(res, -1);
dev_WARN_ONCE(dev, pgmap->altmap.alloc,
"%s: failed to free all reserved pages\n", __func__);
}
@@ -418,7 +421,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
err_pfn_remap:
err_radix:
- pgmap_radix_release(res);
+ pgmap_radix_release(res, pgoff);
devres_free(pgmap);
return ERR_PTR(error);
}
The patch below does not apply to the 4.14-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 77dd66a3c67c93ab401ccc15efff25578be281fd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20H=2E=20Sch=C3=B6nherr?= <jschoenh(a)amazon.de>
Date: Fri, 19 Jan 2018 16:26:33 -0800
Subject: [PATCH] mm: Fix devm_memremap_pages() collision handling
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
If devm_memremap_pages() detects a collision while adding entries
to the radix-tree, we call pgmap_radix_release(). Unfortunately,
the function removes *all* entries for the range -- including the
entries that caused the collision in the first place.
Modify pgmap_radix_release() to take an additional argument to
indicate where to stop, so that only newly added entries are removed
from the tree.
Cc: <stable(a)vger.kernel.org>
Fixes: 9476df7d80df ("mm: introduce find_dev_pagemap()")
Signed-off-by: Jan H. Schönherr <jschoenh(a)amazon.de>
Signed-off-by: Dan Williams <dan.j.williams(a)intel.com>
diff --git a/kernel/memremap.c b/kernel/memremap.c
index 4ef97525a4ff..4849be5f9b3c 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -241,13 +241,16 @@ int device_private_entry_fault(struct vm_area_struct *vma,
EXPORT_SYMBOL(device_private_entry_fault);
#endif /* CONFIG_DEVICE_PRIVATE */
-static void pgmap_radix_release(struct resource *res)
+static void pgmap_radix_release(struct resource *res, unsigned long end_pgoff)
{
unsigned long pgoff, order;
mutex_lock(&pgmap_lock);
- foreach_order_pgoff(res, order, pgoff)
+ foreach_order_pgoff(res, order, pgoff) {
+ if (pgoff >= end_pgoff)
+ break;
radix_tree_delete(&pgmap_radix, PHYS_PFN(res->start) + pgoff);
+ }
mutex_unlock(&pgmap_lock);
synchronize_rcu();
@@ -302,7 +305,7 @@ static void devm_memremap_pages_release(void *data)
mem_hotplug_done();
untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
- pgmap_radix_release(res);
+ pgmap_radix_release(res, -1);
dev_WARN_ONCE(dev, pgmap->altmap.alloc,
"%s: failed to free all reserved pages\n", __func__);
}
@@ -418,7 +421,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
err_pfn_remap:
err_radix:
- pgmap_radix_release(res);
+ pgmap_radix_release(res, pgoff);
devres_free(pgmap);
return ERR_PTR(error);
}
The patch below does not apply to the 4.15-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 77dd66a3c67c93ab401ccc15efff25578be281fd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20H=2E=20Sch=C3=B6nherr?= <jschoenh(a)amazon.de>
Date: Fri, 19 Jan 2018 16:26:33 -0800
Subject: [PATCH] mm: Fix devm_memremap_pages() collision handling
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
If devm_memremap_pages() detects a collision while adding entries
to the radix-tree, we call pgmap_radix_release(). Unfortunately,
the function removes *all* entries for the range -- including the
entries that caused the collision in the first place.
Modify pgmap_radix_release() to take an additional argument to
indicate where to stop, so that only newly added entries are removed
from the tree.
Cc: <stable(a)vger.kernel.org>
Fixes: 9476df7d80df ("mm: introduce find_dev_pagemap()")
Signed-off-by: Jan H. Schönherr <jschoenh(a)amazon.de>
Signed-off-by: Dan Williams <dan.j.williams(a)intel.com>
diff --git a/kernel/memremap.c b/kernel/memremap.c
index 4ef97525a4ff..4849be5f9b3c 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -241,13 +241,16 @@ int device_private_entry_fault(struct vm_area_struct *vma,
EXPORT_SYMBOL(device_private_entry_fault);
#endif /* CONFIG_DEVICE_PRIVATE */
-static void pgmap_radix_release(struct resource *res)
+static void pgmap_radix_release(struct resource *res, unsigned long end_pgoff)
{
unsigned long pgoff, order;
mutex_lock(&pgmap_lock);
- foreach_order_pgoff(res, order, pgoff)
+ foreach_order_pgoff(res, order, pgoff) {
+ if (pgoff >= end_pgoff)
+ break;
radix_tree_delete(&pgmap_radix, PHYS_PFN(res->start) + pgoff);
+ }
mutex_unlock(&pgmap_lock);
synchronize_rcu();
@@ -302,7 +305,7 @@ static void devm_memremap_pages_release(void *data)
mem_hotplug_done();
untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
- pgmap_radix_release(res);
+ pgmap_radix_release(res, -1);
dev_WARN_ONCE(dev, pgmap->altmap.alloc,
"%s: failed to free all reserved pages\n", __func__);
}
@@ -418,7 +421,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
err_pfn_remap:
err_radix:
- pgmap_radix_release(res);
+ pgmap_radix_release(res, pgoff);
devres_free(pgmap);
return ERR_PTR(error);
}
The patch below does not apply to the 4.4-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From abbc3f9395c76d554a9ed27d4b1ebfb5d9b0e4ca Mon Sep 17 00:00:00 2001
From: Harshad Shirwadkar <harshads(a)google.com>
Date: Wed, 10 Jan 2018 00:13:13 -0500
Subject: [PATCH] ext4: fix a race in the ext4 shutdown path
This patch fixes a race between the shutdown path and bio completion
handling. In the ext4 direct io path with async io, after submitting a
bio to the block layer, if journal starting fails,
ext4_direct_IO_write() would bail out pretending that the IO
failed. The caller would have had no way of knowing whether or not the
IO was successfully submitted. So instead, we return -EIOCBQUEUED in
this case. Now, the caller knows that the IO was submitted. The bio
completion handler takes care of the error.
Tested: Ran the shutdown xfstest test 461 in loop for over 2 hours across
4 machines resulting in over 400 runs. Verified that the race didn't
occur. Usually the race was seen in about 20-30 iterations.
Signed-off-by: Harshad Shirwadkar <harshads(a)google.com>
Signed-off-by: Theodore Ts'o <tytso(a)mit.edu>
Cc: stable(a)vger.kernel.org
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 534a9130f625..4c2f8b57bdc7 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3767,10 +3767,18 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter)
/* Credits for sb + inode write */
handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
if (IS_ERR(handle)) {
- /* This is really bad luck. We've written the data
- * but cannot extend i_size. Bail out and pretend
- * the write failed... */
- ret = PTR_ERR(handle);
+ /*
+ * We wrote the data but cannot extend
+ * i_size. Bail out. In async io case, we do
+ * not return error here because we have
+ * already submmitted the corresponding
+ * bio. Returning error here makes the caller
+ * think that this IO is done and failed
+ * resulting in race with bio's completion
+ * handler.
+ */
+ if (!ret)
+ ret = PTR_ERR(handle);
if (inode->i_nlink)
ext4_orphan_del(NULL, inode);
The patch below does not apply to the 4.4-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From d6fa7588fd7a8def4c747c0c574ce85d453e3788 Mon Sep 17 00:00:00 2001
From: Lukas Wunner <lukas(a)wunner.de>
Date: Wed, 24 Jan 2018 19:35:45 +0100
Subject: [PATCH] Revert "apple-gmux: lock iGP IO to protect from vgaarb
changes"
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Commit 4eebd5a4e726 ("apple-gmux: lock iGP IO to protect from vgaarb
changes") amended this driver's ->probe hook to lock decoding of normal
(non-legacy) I/O space accesses to the integrated GPU on dual-GPU
MacBook Pros. The lock stays in place until the driver is unbound.
The change was made to work around an issue with the out-of-tree nvidia
graphics driver (available at http://www.nvidia.com/object/unix.html).
It contains the following sequence in nvidia/nv.c:
#if defined(CONFIG_VGA_ARB) && !defined(NVCPU_PPC64LE)
#if defined(VGA_DEFAULT_DEVICE)
vga_tryget(VGA_DEFAULT_DEVICE, VGA_RSRC_LEGACY_MASK);
#endif
vga_set_legacy_decoding(dev, VGA_RSRC_NONE);
#endif
This code was reported to cause deadlocks with VFIO already in 2013:
https://devtalk.nvidia.com/default/topic/545560
I've reported the issue to Nvidia developers once more in 2017:
https://www.spinics.net/lists/dri-devel/msg138754.html
On the MacBookPro10,1, this code apparently breaks backlight control
(which is handled by apple-gmux via an I/O region starting at 0x700),
as reported by Petri Hodju:
https://bugzilla.kernel.org/show_bug.cgi?id=86121
I tried to replicate Petri's observations on my MacBook9,1, which uses
the same Intel Ivy Bridge + Nvidia GeForce GT 650M architecture, to no
avail. On my machine apple-gmux' I/O region remains accessible even
with the nvidia driver loaded and commit 4eebd5a4e726 reverted.
Petri reported that apple-gmux becomes accessible again after a
suspend/resume cycle because the BIOS changed the VGA routing on the
root port to the Nvidia GPU. Perhaps this is a BIOS issue after all
that can be fixed with an update?
In any case, the change made by commit 4eebd5a4e726 has turned out to
cause two new issues:
* Wilfried Klaebe reports a deadlock when launching Xorg because it
opens /dev/vga_arbiter and calls vga_get(), but apple-gmux is holding
a lock on I/O space indefinitely. It looks like apple-gmux' current
behavior is an abuse of the vgaarb API as locks are not meant to be
held for longer periods:
https://bugzilla.kernel.org/show_bug.cgi?id=88861#c11https://bugzilla.kernel.org/attachment.cgi?id=217541
* On dual GPU MacBook Pros introduced since 2013, the integrated GPU is
powergated on boot und thus becomes invisible to Linux unless a custom
EFI protocol is used to leave it powered on. (A patch exists but is
not in mainline yet due to several negative side effects.) On these
machines, locking I/O to the integrated GPU (as done by 4eebd5a4e726)
fails and backlight control is therefore broken:
https://bugzilla.kernel.org/show_bug.cgi?id=105051
So let's revert commit 4eebd5a4e726 please. Users experiencing the
issue with the proprietary nvidia driver can comment out the above-
quoted problematic code as a workaround (or try updating the BIOS).
Cc: Petri Hodju <petrihodju(a)yahoo.com>
Cc: Bjorn Helgaas <bhelgaas(a)google.com>
Cc: Bruno Prémont <bonbons(a)linux-vserver.org>
Cc: Andy Ritger <aritger(a)nvidia.com>
Cc: Ronald Tschalär <ronald(a)innovation.ch>
Tested-by: Wilfried Klaebe <linux-kernel(a)lebenslange-mailadresse.de>
Signed-off-by: Lukas Wunner <lukas(a)wunner.de>
Cc: stable(a)vger.kernel.org
Signed-off-by: Darren Hart (VMware) <dvhart(a)infradead.org>
diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index 623d322447a2..7c4eb86c851e 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -24,7 +24,6 @@
#include <linux/delay.h>
#include <linux/pci.h>
#include <linux/vga_switcheroo.h>
-#include <linux/vgaarb.h>
#include <acpi/video.h>
#include <asm/io.h>
@@ -54,7 +53,6 @@ struct apple_gmux_data {
bool indexed;
struct mutex index_lock;
- struct pci_dev *pdev;
struct backlight_device *bdev;
/* switcheroo data */
@@ -599,23 +597,6 @@ static int gmux_resume(struct device *dev)
return 0;
}
-static struct pci_dev *gmux_get_io_pdev(void)
-{
- struct pci_dev *pdev = NULL;
-
- while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev))) {
- u16 cmd;
-
- pci_read_config_word(pdev, PCI_COMMAND, &cmd);
- if (!(cmd & PCI_COMMAND_IO))
- continue;
-
- return pdev;
- }
-
- return NULL;
-}
-
static int is_thunderbolt(struct device *dev, void *data)
{
return to_pci_dev(dev)->is_thunderbolt;
@@ -631,7 +612,6 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
int ret = -ENXIO;
acpi_status status;
unsigned long long gpe;
- struct pci_dev *pdev = NULL;
if (apple_gmux_data)
return -EBUSY;
@@ -682,7 +662,7 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
ver_minor = (version >> 16) & 0xff;
ver_release = (version >> 8) & 0xff;
} else {
- pr_info("gmux device not present or IO disabled\n");
+ pr_info("gmux device not present\n");
ret = -ENODEV;
goto err_release;
}
@@ -690,23 +670,6 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
pr_info("Found gmux version %d.%d.%d [%s]\n", ver_major, ver_minor,
ver_release, (gmux_data->indexed ? "indexed" : "classic"));
- /*
- * Apple systems with gmux are EFI based and normally don't use
- * VGA. In addition changing IO+MEM ownership between IGP and dGPU
- * disables IO/MEM used for backlight control on some systems.
- * Lock IO+MEM to GPU with active IO to prevent switch.
- */
- pdev = gmux_get_io_pdev();
- if (pdev && vga_tryget(pdev,
- VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM)) {
- pr_err("IO+MEM vgaarb-locking for PCI:%s failed\n",
- pci_name(pdev));
- ret = -EBUSY;
- goto err_release;
- } else if (pdev)
- pr_info("locked IO for PCI:%s\n", pci_name(pdev));
- gmux_data->pdev = pdev;
-
memset(&props, 0, sizeof(props));
props.type = BACKLIGHT_PLATFORM;
props.max_brightness = gmux_read32(gmux_data, GMUX_PORT_MAX_BRIGHTNESS);
@@ -822,10 +785,6 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
err_notify:
backlight_device_unregister(bdev);
err_release:
- if (gmux_data->pdev)
- vga_put(gmux_data->pdev,
- VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM);
- pci_dev_put(pdev);
release_region(gmux_data->iostart, gmux_data->iolen);
err_free:
kfree(gmux_data);
@@ -845,11 +804,6 @@ static void gmux_remove(struct pnp_dev *pnp)
&gmux_notify_handler);
}
- if (gmux_data->pdev) {
- vga_put(gmux_data->pdev,
- VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM);
- pci_dev_put(gmux_data->pdev);
- }
backlight_device_unregister(gmux_data->bdev);
release_region(gmux_data->iostart, gmux_data->iolen);
The patch below does not apply to the 4.9-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From d6fa7588fd7a8def4c747c0c574ce85d453e3788 Mon Sep 17 00:00:00 2001
From: Lukas Wunner <lukas(a)wunner.de>
Date: Wed, 24 Jan 2018 19:35:45 +0100
Subject: [PATCH] Revert "apple-gmux: lock iGP IO to protect from vgaarb
changes"
MIME-Version: 1.0
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Commit 4eebd5a4e726 ("apple-gmux: lock iGP IO to protect from vgaarb
changes") amended this driver's ->probe hook to lock decoding of normal
(non-legacy) I/O space accesses to the integrated GPU on dual-GPU
MacBook Pros. The lock stays in place until the driver is unbound.
The change was made to work around an issue with the out-of-tree nvidia
graphics driver (available at http://www.nvidia.com/object/unix.html).
It contains the following sequence in nvidia/nv.c:
#if defined(CONFIG_VGA_ARB) && !defined(NVCPU_PPC64LE)
#if defined(VGA_DEFAULT_DEVICE)
vga_tryget(VGA_DEFAULT_DEVICE, VGA_RSRC_LEGACY_MASK);
#endif
vga_set_legacy_decoding(dev, VGA_RSRC_NONE);
#endif
This code was reported to cause deadlocks with VFIO already in 2013:
https://devtalk.nvidia.com/default/topic/545560
I've reported the issue to Nvidia developers once more in 2017:
https://www.spinics.net/lists/dri-devel/msg138754.html
On the MacBookPro10,1, this code apparently breaks backlight control
(which is handled by apple-gmux via an I/O region starting at 0x700),
as reported by Petri Hodju:
https://bugzilla.kernel.org/show_bug.cgi?id=86121
I tried to replicate Petri's observations on my MacBook9,1, which uses
the same Intel Ivy Bridge + Nvidia GeForce GT 650M architecture, to no
avail. On my machine apple-gmux' I/O region remains accessible even
with the nvidia driver loaded and commit 4eebd5a4e726 reverted.
Petri reported that apple-gmux becomes accessible again after a
suspend/resume cycle because the BIOS changed the VGA routing on the
root port to the Nvidia GPU. Perhaps this is a BIOS issue after all
that can be fixed with an update?
In any case, the change made by commit 4eebd5a4e726 has turned out to
cause two new issues:
* Wilfried Klaebe reports a deadlock when launching Xorg because it
opens /dev/vga_arbiter and calls vga_get(), but apple-gmux is holding
a lock on I/O space indefinitely. It looks like apple-gmux' current
behavior is an abuse of the vgaarb API as locks are not meant to be
held for longer periods:
https://bugzilla.kernel.org/show_bug.cgi?id=88861#c11https://bugzilla.kernel.org/attachment.cgi?id=217541
* On dual GPU MacBook Pros introduced since 2013, the integrated GPU is
powergated on boot und thus becomes invisible to Linux unless a custom
EFI protocol is used to leave it powered on. (A patch exists but is
not in mainline yet due to several negative side effects.) On these
machines, locking I/O to the integrated GPU (as done by 4eebd5a4e726)
fails and backlight control is therefore broken:
https://bugzilla.kernel.org/show_bug.cgi?id=105051
So let's revert commit 4eebd5a4e726 please. Users experiencing the
issue with the proprietary nvidia driver can comment out the above-
quoted problematic code as a workaround (or try updating the BIOS).
Cc: Petri Hodju <petrihodju(a)yahoo.com>
Cc: Bjorn Helgaas <bhelgaas(a)google.com>
Cc: Bruno Prémont <bonbons(a)linux-vserver.org>
Cc: Andy Ritger <aritger(a)nvidia.com>
Cc: Ronald Tschalär <ronald(a)innovation.ch>
Tested-by: Wilfried Klaebe <linux-kernel(a)lebenslange-mailadresse.de>
Signed-off-by: Lukas Wunner <lukas(a)wunner.de>
Cc: stable(a)vger.kernel.org
Signed-off-by: Darren Hart (VMware) <dvhart(a)infradead.org>
diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index 623d322447a2..7c4eb86c851e 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -24,7 +24,6 @@
#include <linux/delay.h>
#include <linux/pci.h>
#include <linux/vga_switcheroo.h>
-#include <linux/vgaarb.h>
#include <acpi/video.h>
#include <asm/io.h>
@@ -54,7 +53,6 @@ struct apple_gmux_data {
bool indexed;
struct mutex index_lock;
- struct pci_dev *pdev;
struct backlight_device *bdev;
/* switcheroo data */
@@ -599,23 +597,6 @@ static int gmux_resume(struct device *dev)
return 0;
}
-static struct pci_dev *gmux_get_io_pdev(void)
-{
- struct pci_dev *pdev = NULL;
-
- while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev))) {
- u16 cmd;
-
- pci_read_config_word(pdev, PCI_COMMAND, &cmd);
- if (!(cmd & PCI_COMMAND_IO))
- continue;
-
- return pdev;
- }
-
- return NULL;
-}
-
static int is_thunderbolt(struct device *dev, void *data)
{
return to_pci_dev(dev)->is_thunderbolt;
@@ -631,7 +612,6 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
int ret = -ENXIO;
acpi_status status;
unsigned long long gpe;
- struct pci_dev *pdev = NULL;
if (apple_gmux_data)
return -EBUSY;
@@ -682,7 +662,7 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
ver_minor = (version >> 16) & 0xff;
ver_release = (version >> 8) & 0xff;
} else {
- pr_info("gmux device not present or IO disabled\n");
+ pr_info("gmux device not present\n");
ret = -ENODEV;
goto err_release;
}
@@ -690,23 +670,6 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
pr_info("Found gmux version %d.%d.%d [%s]\n", ver_major, ver_minor,
ver_release, (gmux_data->indexed ? "indexed" : "classic"));
- /*
- * Apple systems with gmux are EFI based and normally don't use
- * VGA. In addition changing IO+MEM ownership between IGP and dGPU
- * disables IO/MEM used for backlight control on some systems.
- * Lock IO+MEM to GPU with active IO to prevent switch.
- */
- pdev = gmux_get_io_pdev();
- if (pdev && vga_tryget(pdev,
- VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM)) {
- pr_err("IO+MEM vgaarb-locking for PCI:%s failed\n",
- pci_name(pdev));
- ret = -EBUSY;
- goto err_release;
- } else if (pdev)
- pr_info("locked IO for PCI:%s\n", pci_name(pdev));
- gmux_data->pdev = pdev;
-
memset(&props, 0, sizeof(props));
props.type = BACKLIGHT_PLATFORM;
props.max_brightness = gmux_read32(gmux_data, GMUX_PORT_MAX_BRIGHTNESS);
@@ -822,10 +785,6 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
err_notify:
backlight_device_unregister(bdev);
err_release:
- if (gmux_data->pdev)
- vga_put(gmux_data->pdev,
- VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM);
- pci_dev_put(pdev);
release_region(gmux_data->iostart, gmux_data->iolen);
err_free:
kfree(gmux_data);
@@ -845,11 +804,6 @@ static void gmux_remove(struct pnp_dev *pnp)
&gmux_notify_handler);
}
- if (gmux_data->pdev) {
- vga_put(gmux_data->pdev,
- VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM);
- pci_dev_put(gmux_data->pdev);
- }
backlight_device_unregister(gmux_data->bdev);
release_region(gmux_data->iostart, gmux_data->iolen);