Re: [PATCH v6 14/23] vhost-user-gpu: skip VHOST_USER_GPU_UPDATE when !PIXMAN

[Marc-André Lureau]

Hi

On Thu, Oct 26, 2023 at 12:58 AM BALATON Zoltan <balaton@eik.bme.hu> wrote:
>
> On Wed, 25 Oct 2023, marcandre.lureau@redhat.com wrote:
> > From: Marc-André Lureau <marcandre.lureau@redhat.com>
> >
> > This simply means that 2d drawing updates won't be handled, but 3d
> > should work.
>
> Does this silently break guest display when !PIXMAN or I don't understand
> what this means (I don't know how this device works). If it causes missing
> display without PIXMAN should this need pixman or print a warning about
> that?

The 2D updates will not be displayed. There will be a warning of
"unhandled message 8" for each update.

3D updates are still handled, so you could skip the boot phase until
the guest 3d driver is loaded, or you could have a vhost-user-gpu
backend that only provides 3D updates (aka dmabuf)

>
> Regards,
> BALATON Zoltan
>
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > Acked-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> > hw/display/vhost-user-gpu.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/hw/display/vhost-user-gpu.c b/hw/display/vhost-user-gpu.c
> > index 1150521d9d..709c8a02a1 100644
> > --- a/hw/display/vhost-user-gpu.c
> > +++ b/hw/display/vhost-user-gpu.c
> > @@ -307,6 +307,7 @@ vhost_user_gpu_handle_display(VhostUserGPU *g, 
> > VhostUserGpuMsg *msg)
> >         dpy_gl_update(con, m->x, m->y, m->width, m->height);
> >         break;
> >     }
> > +#ifdef CONFIG_PIXMAN
> >     case VHOST_USER_GPU_UPDATE: {
> >         VhostUserGpuUpdate *m = &msg->payload.update;
> >
> > @@ -334,6 +335,7 @@ vhost_user_gpu_handle_display(VhostUserGPU *g, 
> > VhostUserGpuMsg *msg)
> >         }
> >         break;
> >     }
> > +#endif
> >     default:
> >         g_warning("unhandled message %d %d", msg->request, msg->size);
> >     }
> >



-- 
Marc-André Lureau