Re: [PATCH 3/8] ui/gtk-gl-area: Remove extra draw call in refresh

["Alex Bennée" <alex.bennee@linaro.org>]

Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp> writes:

> On 2025/10/14 20:12, Alex Bennée wrote:
>> From: Dongwon Kim <dongwon.kim@intel.com>
>> This partially reverts commit
>> 77bf310084dad38b3a2badf01766c659056f1cf2
>> which causes some guest display corruption when gtk-gl-area
>> is used for GTK rendering (e.g. Wayland Compositor) possibly due to
>> simulataneous accesses on the guest frame buffer by host compositor
>> and the guest.
>> Fixes: 77bf310084 ("ui/gtk: Draw guest frame at refresh cycle")
>> Reported-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
>> Reported-by: Alex Bennée <alex.bennee@linaro.org>
>> Tested-by: Alex Bennée <alex.bennee@linaro.org>
>> Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
>> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
>> Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
>> Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
>> Cc: Vivek Kasireddy <vivek.kasireddy@intel.com>
>> Signed-off-by: Dongwon Kim <dongwon.kim@intel.com>
>> Message-Id: <20250214170813.2234754-1-dongwon.kim@intel.com>
>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>> Message-ID: <20250603110204.838117-12-alex.bennee@linaro.org>
>> Cc: qemu-stable@nongnu.org
>> ---
>>   ui/gtk-gl-area.c | 1 -
>>   1 file changed, 1 deletion(-)
>> diff --git a/ui/gtk-gl-area.c b/ui/gtk-gl-area.c
>> index 05fc38096ec..9a11c9b4d18 100644
>> --- a/ui/gtk-gl-area.c
>> +++ b/ui/gtk-gl-area.c
>> @@ -165,7 +165,6 @@ void gd_gl_area_refresh(DisplayChangeListener *dcl)
>>         if (vc->gfx.guest_fb.dmabuf &&
>>           qemu_dmabuf_get_draw_submitted(vc->gfx.guest_fb.dmabuf)) {
>> -        gd_gl_area_draw(vc);
>
>
> I suggested adding code comment for the lack of gd_gl_area_draw() here
> a while ago but it seems it is missed since then:
> https://lore.kernel.org/qemu-devel/63911dcc-482b-45c5-9468-120ae3df691b@daynix.com/
>
> The removal of this function call itself looks good to me.

What comment would you like - its not clear from the thread what I
should add.

>
>>           return;
>>       }
>>   

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro