> +static Bool
> +can_exchange(ScrnInfoPtr scrn, DrawablePtr draw,
> + DRI2BufferPtr front, DRI2BufferPtr back)
> +{
[...]
> + if (!update_front(draw, front))
> + return FALSE;
I know you just copied this from -ati/amdgpu, but: I don't think
can_exchange should call update_front, or the front buffer may be
updated even though the flip later fails.
[yuq] so you mean I can just drop update_front here and use "front"
directly?
> + /* Post damage on the front buffer so that listeners, such
> + * as DisplayLink know take a copy and shove it over the USB.
> + * also for sw cursors.
> + */
SW cursors cannot work correctly with page flipping. For that reason,
xf86-video-ati/amdgpu disable page flipping while there's an SW cursor.
[yuq] why? Is the problem in kernel or xserver?
Regards,
Qiang
