diff options
| author | Javier Martinez Canillas | 2022-06-07 20:23:36 +0200 |
|---|---|---|
| committer | Javier Martinez Canillas | 2022-06-09 16:20:12 +0200 |
| commit | 873eb3b11860aada97ddc02d48b54522b92848db (patch) | |
| tree | 7e156101a538d0bdac520bec37709916eed95a9a /drivers/video | |
| parent | bc824922b264aff40eba8c160972ee07a95e7dd4 (diff) | |
fbdev: Disable sysfb device registration when removing conflicting FBs
The platform devices registered by sysfb match with firmware-based DRM or
fbdev drivers, that are used to have early graphics using a framebuffer
provided by the system firmware.
DRM or fbdev drivers later are probed and remove conflicting framebuffers,
leading to these platform devices for generic drivers to be unregistered.
But the current solution has a race, since the sysfb_init() function could
be called after a DRM or fbdev driver is probed and request to unregister
the devices for drivers with conflicting framebuffes.
To prevent this, disable any future sysfb platform device registration by
calling sysfb_disable(), if a driver requests to remove the conflicting
framebuffers.
Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220607182338.344270-4-javierm@redhat.com
Diffstat (limited to 'drivers/video')
| -rw-r--r-- | drivers/video/fbdev/core/fbmem.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 2fda5917c212..e0720fef0ee6 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -19,6 +19,7 @@ #include <linux/kernel.h> #include <linux/major.h> #include <linux/slab.h> +#include <linux/sysfb.h> #include <linux/mm.h> #include <linux/mman.h> #include <linux/vt.h> @@ -1764,6 +1765,17 @@ int remove_conflicting_framebuffers(struct apertures_struct *a, do_free = true; } + /* + * 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(); + mutex_lock(®istration_lock); do_remove_conflicting_framebuffers(a, name, primary); mutex_unlock(®istration_lock); |