drm/panic: Add support to scanout buffer as array of pages

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Some drivers like virtio-gpu, don't map the scanout buffer in the
kernel. Calling vmap() in a panic handler is not safe, and writing an
atomic_vmap() API is more complex than expected [1].
So instead, pass the array of pages of the scanout buffer to the
panic handler, and map only one page at a time to draw the pixels.
This is obviously slow, but acceptable for a panic handler.

[1] https://lore.kernel.org/dri-devel/20250305152555.318159-1-ryasuoka@redhat.com/

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Simona Vetter <simona@ffwll.ch>
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://lore.kernel.org/r/20250407140138.162383-3-jfalempe@redhat.com

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Jocelyn Falempe 2025-04-07 15:42:26 +02:00

parent 8702048bb8

commit c9ff280879

2 changed files with 147 additions and 7 deletions

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144

drivers/gpu/drm/drm_panic.c

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12

include/drm/drm_panic.h

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