Re: [RFC v1 3/4] swiotlb: Allow dynamic allocation of bounce buffers

[Petr Tesařík]

On Thu, 06 Apr 2023 11:44:55 +0000
Juerg Haefliger <juergh@xxxxxxxxx> wrote:

> On Fri, 31 Mar 2023 11:00:43 +0200
> Petr Tesařík <petr@xxxxxxxxxxx> wrote:
> 
> > Hi Juerg,
> >
> > On Fri, 31 Mar 2023 07:26:09 +0000
> > Juerg Haefliger <juergh@xxxxxxxxx> wrote:
> >  
> > > On Tue, 28 Mar 2023 09:54:35 +0200
> > > Petr Tesarik <petrtesarik@xxxxxxxxxxxxxxx> wrote:
> > >
> > >[...]  
> > > > Anyway, I suspected that the buffers need not be imported into the vc4
> > > > driver (also hinted by Eric Anholt in a 2018 blog post [1]), and it
> > > > seems I was right. I encountered the issue with Ubuntu 22.10; I
> > > > installed latest openSUSE Tumbleweed yesterday, and I was not able to
> > > > reproduce the issue there, most likely because the Mesa drivers have
> > > > been fixed meanwhile. This makes the specific case of the Raspberry Pi 4
> > > > drivers moot. The issue may still affect other combinations of drivers,
> > > > but I don't have any other real-world example ATM.  
> > >
> > > I'm only seeing this problem with Wayland, no issue when switching Ubuntu to
> > > X. It seems Tumbleweed is using X by default.  
> >
> > I know; I was the team lead of SUSE low-level graphics engineers until
> > end of last year... I have just double-checked, but this output of
> > wayland-info in the GNOME session accessed over RDP is quite convincing:  
> 
> It sure is but how did you get that??

I'm sorry for late reply.

Yes, the default is GNOME on X.org, but you can change it on the GDM
login screen. After choosing your account, a settings gear icon appears
in the lower right corner. Click on it and choose GNOME. That starts a
Wayland session.

HTH
Petr T