[PATCH V3] video/aperture: optionally match the device in sysfb_disable()

[Javier Martinez Canillas]

Alex Deucher <alexander.deucher at amd.com> writes:

Hello Alex,

> In aperture_remove_conflicting_pci_devices(), we currently only
> call sysfb_disable() on vga class devices.  This leads to the
> following problem when the pimary device is not VGA compatible:
>
> 1. A PCI device with a non-VGA class is the boot display
> 2. That device is probed first and it is not a VGA device so
>    sysfb_disable() is not called, but the device resources
>    are freed by aperture_detach_platform_device()
> 3. Non-primary GPU has a VGA class and it ends up calling sysfb_disable()
> 4. NULL pointer dereference via sysfb_disable() since the resources
>    have already been freed by aperture_detach_platform_device() when
>    it was called by the other device.
>
> Fix this by passing a device pointer to sysfb_disable() and checking
> the device to determine if we should execute it or not.
>
> v2: Fix build when CONFIG_SCREEN_INFO is not set
> v3: Move device check into the mutex
>     Drop primary variable in aperture_remove_conflicting_pci_devices()
>     Drop __init on pci sysfb_pci_dev_is_enabled()
>
> Fixes: 5ae3716cfdcd ("video/aperture: Only remove sysfb on the default vga pci device")
> Cc: Javier Martinez Canillas <javierm at redhat.com>
> Cc: Thomas Zimmermann <tzimmermann at suse.de>
> Cc: Helge Deller <deller at gmx.de>
> Cc: Sam Ravnborg <sam at ravnborg.org>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> Cc: stable at vger.kernel.org
> ---

This version looks good to me. Thanks!

Reviewed-by: Javier Martinez Canillas <javierm at redhat.com>

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat