Re: [PATCH 4/7] drm/meson: plane: add support for AFBC mode for OSD1 plane

[Brian Starkey <Brian.Starkey@arm.com>]

Hi Neil,

On Fri, Oct 11, 2019 at 02:07:01PM +0200, Neil Armstrong wrote:
> On 11/10/2019 12:56, Brian Starkey wrote:
> > Hi,
> > 
> > On Fri, Oct 11, 2019 at 11:14:43AM +0200, Neil Armstrong wrote:
> >> Hi Brian,
> >>
> >> On 11/10/2019 10:41, Brian Starkey wrote:
> >>> Hi Neil,
> >>>
> >>> On Thu, Oct 10, 2019 at 03:41:15PM +0200, Neil Armstrong wrote:

[snip]

> >> You'll have to tell us if the closed libMali handling AFBC would accept
> >> ARGB8888 as format to render with AFBC enabled, if not you're right
> >> I'll discard XRGB8888/ARGB8888 for AFBC buffers completely.
> >>
> >> But it the libMali chooses tt generate an ARGB8888 buffer whatever
> >> ARGB8888/XRGB8888/ABGR888/XBGR888 is asked, then no I'll keep it that way.
> >>
> > 
> > Yeah, I'll try and get clarity on this. It's not at all clear to me
> > either. When you say "accept ARGB8888 as format to render with AFBC
> > enabled", which API are you referring to, just so I can be clear? Do
> > you have an example of some code you're using to render AFBC with the
> > GPU blob?
> 
> Let's take kmscube using EGL and GBM.
> 
> The buffer is allocated using gbm_surface_create_with_modifiers(),
> but the gbm implementation is vendor specified.
> 
> Then the surface is passed to eglCreateWindowSurface().
> Then the format is matched using eglGetConfigAttrib() with the
> returned configs.
> 
> Here support on the gbm and EGL implementation.
> 

Is this a use-case that works on your platform today?

I went and asked around. An Arm gbm implementation supporting AFBC
will reject AFBC allocations for orders other than (DRM-convention)
BGR.

Thanks,
-Brian

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