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 <stable@xxxxxxxxxxxxxxx> know about it.
>From tzimmermann@xxxxxxx Wed Oct 26 16:46:12 2022
From: Thomas Zimmermann <tzimmermann@xxxxxxx>
Date: Wed, 26 Oct 2022 16:44:48 +0200
Subject: [PATCH v2] video/aperture: Call sysfb_disable() before removing PCI devices
To: javierm@xxxxxxxxxx, deller@xxxxxx, sashal@xxxxxxxxxx, gregkh@xxxxxxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx, Thomas Zimmermann <tzimmermann@xxxxxxx>, Andreas Thalhammer <andreas.thalhammer-linux@xxxxxxx>, Thorsten Leemhuis <regressions@xxxxxxxxxxxxx>, Zack Rusin <zackr@xxxxxxxxxx>, Daniel Vetter <daniel.vetter@xxxxxxxx>, Daniel Vetter <daniel@xxxxxxxx>, Sam Ravnborg <sam@xxxxxxxxxxxx>, Alex Deucher <alexander.deucher@xxxxxxx>, Zhen Lei <thunder.leizhen@xxxxxxxxxx>, Changcheng Deng <deng.changcheng@xxxxxxxxxx>, Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>, Maxime Ripard <mripard@xxxxxxxxxx>, dri-devel@xxxxxxxxxxxxxxxxxxxxx, linux-fbdev@xxxxxxxxxxxxxxx
Message-ID: <20221026144448.424-1-tzimmermann@xxxxxxx>
From: Thomas Zimmermann <tzimmermann@xxxxxxx>
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 <andreas.thalhammer-linux@xxxxxxx>
Reported-by: Thorsten Leemhuis <regressions@xxxxxxxxxxxxx>
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Tested-by: Andreas Thalhammer <andreas.thalhammer-linux@xxxxxxx>
Fixes: cfecfc98a78d ("video/aperture: Disable and unregister sysfb devices via aperture helpers")
Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
Cc: Javier Martinez Canillas <javierm@xxxxxxxxxx>
Cc: Zack Rusin <zackr@xxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: Sam Ravnborg <sam@xxxxxxxxxxxx>
Cc: Helge Deller <deller@xxxxxx>
Cc: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
Cc: Changcheng Deng <deng.changcheng@xxxxxxxxxx>
Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Cc: Maxime Ripard <mripard@xxxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: Sasha Levin <sashal@xxxxxxxxxx>
Cc: linux-fbdev@xxxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # v6.0.3+
Link: https://lore.kernel.org/dri-devel/d6afe54b-f8d7-beb2-3609-186e566cbfac@xxxxxxx/T/#t # [1]
Link: https://patchwork.freedesktop.org/series/106040/ # [2]
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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 tzimmermann@xxxxxxx are
queue-6.0/video-aperture-call-sysfb_disable-before-removing-pci-devices.patch
