Hi Thomas,
quick response as always! :)
On Wed, Sep 4, 2024 at 11:31 AM Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:
> Deferred I/O requires struct page for framebuffer memory, which is
> not guaranteed for all DMA ranges. We thus only install deferred I/O
> if we have a framebuffer that requires it.
>
> A reported bug affected the ipu-v3 and pl111 drivers, which have video
> memory in either Normal or HighMem zones
>
> [ 0.000000] Zone ranges:
> [ 0.000000] Normal [mem 0x0000000010000000-0x000000003fffffff]
> [ 0.000000] HighMem [mem 0x0000000040000000-0x000000004fffffff]
>
> where deferred I/O only works correctly with HighMem. See the Closes
> tags for bug reports.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
> Fixes: 808a40b69468 ("drm/fbdev-dma: Implement damage handling and deferred I/O")
> Reported-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
> Closes: https://lore.kernel.org/all/23636953.6Emhk5qWAg@steina-w/
> Reported-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> Closes: https://lore.kernel.org/dri-devel/CACRpkdb+hb9AGavbWpY-=uQQ0apY9en_tWJioPKf_fAbXMP4Hg@xxxxxxxxxxxxxx/
> Tested-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
> Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
> Cc: Javier Martinez Canillas <javierm@xxxxxxxxxx>
> Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> Cc: Maxime Ripard <mripard@xxxxxxxxxx>
It works like a charm and LGTM.
Tested-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Yours,
Linus Walleij
