[PATCH v4 01/10] drm/fourcc: Add AFBC yuv fourccs for Mali

[Brian Starkey]

On Mon, Mar 18, 2019 at 07:00:57PM +0000, Brian Starkey wrote:
> On Mon, Mar 18, 2019 at 07:12:24PM +0100, Maarten Lankhorst wrote:
> > Op 18-03-2019 om 16:40 schreef Brian Starkey:
> > > Hi,
> > >
> > > On Mon, Mar 18, 2019 at 11:17:55AM +0100, Maarten Lankhorst wrote:
> > >
> > > <snip>
> > >
> > >> Hey..
> > >>
> > >> There's a conflict with this patch and the merge of topic/hdr-formats, resulting in double definitions for Y210, Y410 and P010.
> > >>
> > >> Worse still is that one has set has_alpha to true for Y41x and other to false.
> > >>
> > >> ~Maarten
> > >>
> > > Oh that's sad :-( I think this fell through the cracks on our side
> > > when someone left our team. Also turns out I'm not subscribed to
> > > igt-dev.
> > >
> > > I see you commented the same on one of the previous patches, and that
> > > there was some discussion of this on the test patches too.
> > >
> > > I have been referring to Microsoft's page[1] as "the" source for these
> > > formats, which does indeed call out Y410 as having 2 bits of alpha.
> > > Our GPU expects alpha.
> > 
> > Ah. Yeah there has been discussion on whether there was supposed to be alpha or not, but the original discussion on HDR formats has been completely ignored by arm.
> > 
> > The patch had originally a few arm devs on cc and was sent to dri-devel with linux-media cc'd. Was sad to see it completely ignored so after having been sent twice I pushed it.
> 
> That's the kernel patch(es)? It looks like I did receive them via
> dri-devel, and Ayan was Cc'd on two of the series', but it's
> disingenuous to say they had "a few Arm devs".
> 
> I first submitted this patch with Y410 to dri-devel back in August,
> and since then it's been sent 8 times by my count (with you on Cc on
> all of them!), and all have been similarly completely ignored; so I'm
> sorry but I don't think you can put the blame entirely with Arm here.
> 
> > 
> > > Was there a specific reason for opting to change the test instead of
> > > the definition? Any way to get this changed now?
> > >
> > > It doesn't seem that sensible for the kernel to call something Y410
> > > which doesn't match an "existing" definition by the same name. If
> > > alpha needs to be ignored on scanout, the alpha blend mode property
> > > can be used (more archaeology - I see that was still giving CRC
> > > failures, but that might be a "known issue" for all YUV on your HW?)
> > 
> > Were a few bugs, but should be fixed now. :)
> > 
> > Well only that we didn't have hw supporting alpha, and didn't hear back from others so we went without alpha.
> 
> So what do you suggest? Can we change it, or we need to forever live
> with divergent definitions in DRM vs elsewhere?
> 
> Gstreamer appears to have a Y410 definition including alpha[1], and
> there's the aforementioned Microsoft page too.
> 
> To me it looks like we should change DRM, and if your HW supports
> something that's "almost but not quite" Y410 then you need a different
> name or only allow alpha-blend-mode "none".
> 
> Thanks,
> -Brian
> 
> [1] https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/commit/0ac7d1187b234e86157ad74937c249a3c016807c

Eh. I'm not familiar enough with the gitlab UI. Looks like this didn't
merge in GStreamer so far.

> > 
> > > -Brian
> > >
> > > [1] https://docs.microsoft.com/en-us/windows/desktop/medfound/10-bit-and-16-bit-yuv-video-formats#444-formats
> > 
> >