From: Thomas Zimmermann Date: Wed, 26 Oct 2022 14:44:48 +0000 (+0200) Subject: video/aperture: Call sysfb_disable() before removing PCI devices X-Git-Tag: v6.0.6~94 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=25a6688f27ff54f97adf7cce1d7e18c38bf51eb4;p=thirdparty%2Fkernel%2Fstable.git video/aperture: Call sysfb_disable() before removing PCI devices 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: ? 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 ... 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: ? 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 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 Reported-by: Thorsten Leemhuis Signed-off-by: Thomas Zimmermann Tested-by: Andreas Thalhammer Fixes: cfecfc98a78d ("video/aperture: Disable and unregister sysfb devices via aperture helpers") Cc: Thomas Zimmermann Cc: Javier Martinez Canillas Cc: Zack Rusin Cc: Daniel Vetter Cc: Daniel Vetter Cc: Sam Ravnborg Cc: Helge Deller Cc: Alex Deucher Cc: Zhen Lei Cc: Changcheng Deng Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: dri-devel@lists.freedesktop.org Cc: Sasha Levin Cc: linux-fbdev@vger.kernel.org Cc: # v6.0.3+ Link: https://lore.kernel.org/dri-devel/d6afe54b-f8d7-beb2-3609-186e566cbfac@gmx.net/T/#t # [1] Link: https://patchwork.freedesktop.org/series/106040/ # [2] Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/video/aperture.c b/drivers/video/aperture.c index 101e13c2cf41c..9223d3d4089f1 100644 --- a/drivers/video/aperture.c +++ b/drivers/video/aperture.c @@ -357,6 +357,17 @@ int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const char *na if (ret) 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.