This is a note to let you know that I've just added the patch titled
[PATCH v2] video/aperture: Call sysfb_disable() before removing PCI devices
to the 6.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
video-aperture-call-sysfb_disable-before-removing-pci-devices.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From [email protected] Wed Oct 26 16:46:12 2022
From: Thomas Zimmermann <[email protected]>
Date: Wed, 26 Oct 2022 16:44:48 +0200
Subject: [PATCH v2] video/aperture: Call sysfb_disable() before removing PCI
devices
To: [email protected], [email protected], [email protected],
[email protected]
Cc: [email protected], Thomas Zimmermann <[email protected]>, Andreas
Thalhammer <[email protected]>, Thorsten Leemhuis
<[email protected]>, Zack Rusin <[email protected]>, Daniel Vetter
<[email protected]>, Daniel Vetter <[email protected]>, Sam Ravnborg
<[email protected]>, Alex Deucher <[email protected]>, Zhen Lei
<[email protected]>, Changcheng Deng <[email protected]>,
Maarten Lankhorst <[email protected]>, Maxime Ripard
<[email protected]>, [email protected],
[email protected]
Message-ID: <[email protected]>
From: Thomas Zimmermann <[email protected]>
Call sysfb_disable() from aperture_remove_conflicting_pci_devices()
before removing PCI devices. Without, simpledrm can still bind to
simple-framebuffer devices after the hardware driver has taken over
the hardware. Both drivers interfere with each other and results are
undefined.
Reported modesetting errors [1] are shown below.
---- snap ----
rcu: INFO: rcu_sched detected expedited stalls on CPUs/tasks: { 13-.... } 7
jiffies s: 165 root: 0x2000/.
rcu: blocking rcu_node structures (internal RCU debug):
Task dump for CPU 13:
task:X state:R running task stack: 0 pid: 4242 ppid:
4228 flags:0x00000008
Call Trace:
<TASK>
? commit_tail+0xd7/0x130
? drm_atomic_helper_commit+0x126/0x150
? drm_atomic_commit+0xa4/0xe0
? drm_plane_get_damage_clips.cold+0x1c/0x1c
? drm_atomic_helper_dirtyfb+0x19e/0x280
? drm_mode_dirtyfb_ioctl+0x10f/0x1e0
? drm_mode_getfb2_ioctl+0x2d0/0x2d0
? drm_ioctl_kernel+0xc4/0x150
? drm_ioctl+0x246/0x3f0
? drm_mode_getfb2_ioctl+0x2d0/0x2d0
? __x64_sys_ioctl+0x91/0xd0
? do_syscall_64+0x60/0xd0
? entry_SYSCALL_64_after_hwframe+0x4b/0xb5
</TASK>
...
rcu: INFO: rcu_sched detected expedited stalls on CPUs/tasks: { 13-.... } 30
jiffies s: 169 root: 0x2000/.
rcu: blocking rcu_node structures (internal RCU debug):
Task dump for CPU 13:
task:X state:R running task stack: 0 pid: 4242 ppid:
4228 flags:0x0000400e
Call Trace:
<TASK>
? memcpy_toio+0x76/0xc0
? memcpy_toio+0x1b/0xc0
? drm_fb_memcpy_toio+0x76/0xb0
? drm_fb_blit_toio+0x75/0x2b0
? simpledrm_simple_display_pipe_update+0x132/0x150
? drm_atomic_helper_commit_planes+0xb6/0x230
? drm_atomic_helper_commit_tail+0x44/0x80
? commit_tail+0xd7/0x130
? drm_atomic_helper_commit+0x126/0x150
? drm_atomic_commit+0xa4/0xe0
? drm_plane_get_damage_clips.cold+0x1c/0x1c
? drm_atomic_helper_dirtyfb+0x19e/0x280
? drm_mode_dirtyfb_ioctl+0x10f/0x1e0
? drm_mode_getfb2_ioctl+0x2d0/0x2d0
? drm_ioctl_kernel+0xc4/0x150
? drm_ioctl+0x246/0x3f0
? drm_mode_getfb2_ioctl+0x2d0/0x2d0
? __x64_sys_ioctl+0x91/0xd0
? do_syscall_64+0x60/0xd0
? entry_SYSCALL_64_after_hwframe+0x4b/0xb5
</TASK>
The problem was added by commit 5e0137612430 ("video/aperture: Disable
and unregister sysfb devices via aperture helpers") to v6.0.3 and does
not exist in the mainline branch.
The mainline commit 5e0137612430 ("video/aperture: Disable and
unregister sysfb devices via aperture helpers") has been backported
from v6.0-rc1 to stable v6.0.3 from a larger patch series [2] that
reworks fbdev framebuffer ownership. The backport misses a change to
aperture_remove_conflicting_pci_devices(). Mainline itself is fine,
because the function does not exist there as a result of the patch
series.
Instead of backporting the whole series, fix the additional function.
Reported-by: Andreas Thalhammer <[email protected]>
Reported-by: Thorsten Leemhuis <[email protected]>
Signed-off-by: Thomas Zimmermann <[email protected]>
Tested-by: Andreas Thalhammer <[email protected]>
Fixes: cfecfc98a78d ("video/aperture: Disable and unregister sysfb devices via
aperture helpers")
Cc: Thomas Zimmermann <[email protected]>
Cc: Javier Martinez Canillas <[email protected]>
Cc: Zack Rusin <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Sam Ravnborg <[email protected]>
Cc: Helge Deller <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: Zhen Lei <[email protected]>
Cc: Changcheng Deng <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: Maxime Ripard <[email protected]>
Cc: [email protected]
Cc: Sasha Levin <[email protected]>
Cc: [email protected]
Cc: <[email protected]> # v6.0.3+
Link:
https://lore.kernel.org/dri-devel/[email protected]/T/#t
# [1]
Link: https://patchwork.freedesktop.org/series/106040/ # [2]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/video/aperture.c | 11 +++++++++++
1 file changed, 11 insertions(+)
--- a/drivers/video/aperture.c
+++ b/drivers/video/aperture.c
@@ -358,6 +358,17 @@ int aperture_remove_conflicting_pci_devi
return ret;
/*
+ * If a driver asked to unregister a platform device registered by
+ * sysfb, then can be assumed that this is a driver for a display
+ * that is set up by the system firmware and has a generic driver.
+ *
+ * Drivers for devices that don't have a generic driver will never
+ * ask for this, so let's assume that a real driver for the display
+ * was already probed and prevent sysfb to register devices later.
+ */
+ sysfb_disable();
+
+ /*
* WARNING: Apparently we must kick fbdev drivers before vgacon,
* otherwise the vga fbdev driver falls over.
*/
Patches currently in stable-queue which might be from [email protected] are
queue-6.0/video-aperture-call-sysfb_disable-before-removing-pci-devices.patch
