Re: [PATCH] ui/gtk: skip any extra draw of same guest scanout blob res

[Dongwon Kim <dongwon.kim@intel.com>]

On Fri, Sep 17, 2021 at 12:02:02PM +0200, Gerd Hoffmann wrote:
>   Hi,
> 
> > +    bool      draw_submitted;
> > +    QemuMutex mutex;
> 
> Why the mutex?  I think all the code runs while holding the BQL so it
> should be serialized.

Gerd, I did more experiment and verified mutex is actually not required.
I think I had some wrong belief after seeing some of sync problem
resolved after adding mutex but the code sequence was different at that
time.. I will remove mutex.

> 
> > +#ifdef CONFIG_GBM
> > +        if (dmabuf) {
> > +            qemu_mutex_lock(&dmabuf->mutex);
> > +            if (!dmabuf->draw_submitted) {
> > +                qemu_mutex_unlock(&dmabuf->mutex);
> > +                return;
> > +            } else {
> > +                dmabuf->draw_submitted = false;
> > +            }
> > +        }
> > +#endif
> 
> Factoring out that into helper functions is probably a good idea.  Then
> have stub functions for the CONFIG_GBM=no case and *alot* less #ifdefs
> in the code ...
> 

There are oter places controlled by #ifdef CONFIG_GBM.
What about taking care of CONFIG_GBM altogher after v2 (same but no
mutex) of this patch?

> thanks,
>   Gerd
>