[PATCH 1/5] fbdev: Hot-unplug firmware fb devices on forced removal

[Zack Rusin]

On Mon, 2022-01-24 at 13:36 +0100, Thomas Zimmermann wrote:
> Hot-unplug all firmware-framebuffer devices as part of removing
> them via remove_conflicting_framebuffers() et al. Releases all
> memory regions to be acquired by native drivers.
> 
> Firmware, such as EFI, install a framebuffer while posting the
> computer. After removing the firmware-framebuffer device from fbdev,
> a native driver takes over the hardware and the firmware framebuffer
> becomes invalid.
> 
> Firmware-framebuffer drivers, specifically simplefb, don't release
> their device from Linux' device hierarchy. It still owns the firmware
> framebuffer and blocks the native drivers from loading. This has been
> observed in the vmwgfx driver. [1]
> 
> Initiating a device removal (i.e., hot unplug) as part of
> remove_conflicting_framebuffers() removes the underlying device and
> returns the memory range to the system.
> 
> [1]
> https://lore.kernel.org/dri-devel/20220117180359.18114-1-zack@kde.org/
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> CC: stable at vger.kernel.org # v5.11+

Looks great, thanks!

Reviewed-by: Zack Rusin <zackr at vmware.com>