Re: [PATCH] hw/display/bcm2835_fb: fix fb_use_offsets condition

[Peter Maydell]

On Sat, 13 Jul 2024 at 17:04, SamJakob <me@samjakob.com> wrote:
>
>         It is common practice when implementing double-buffering
>         on VideoCore to do so by multiplying the height of the
>         virtual buffer by the number of virtual screens desired
>         (i.e., two - in the case of double-bufferring).
>
>         At present, this won't work in QEMU because the logic in
>         fb_use_offsets require that both the virtual width and
>         height exceed their physical counterparts.
>
>         This appears to be unintentional/a typo and indeed the
>         comment states; "Experimentally, the hardware seems to
>         do this only if the viewport size is larger than the
>         physical screen". The viewport/virtual size would be
>         larger than the physical size if either virtual dimension
>         were larger than their physical counterparts and not
>         necessarily both.
>
> Signed-off-by: SamJakob <me@samjakob.com>

Thanks for this bugfix; I've applied it to my target-arm.next
queue and it should get upstream within a week or so.

-- PMM