[RFC][PATCH 1/2] drm_hwcomposer: Error out on YUV layer as it would fail for single planes

[Alexandru-Cosmin Gheorghe]

Hi Daniel,

On Fri, Mar 09, 2018 at 09:29:24AM +0000, Daniel Stone wrote:
> Hi John,
> 
> On 8 March 2018 at 19:43, John Stultz <john.stultz at linaro.org> wrote:
> > On Thu, Mar 8, 2018 at 3:10 AM, Robert Foss <robert.foss at collabora.com> wrote:
> >>> @@ -76,8 +76,6 @@ uint32_t
> >>> DrmGenericImporter::ConvertHalFormatToDrm(uint32_t hal_format) {
> >>>         return DRM_FORMAT_ABGR8888;
> >>>       case HAL_PIXEL_FORMAT_RGB_565:
> >>>         return DRM_FORMAT_BGR565;
> >>> -    case HAL_PIXEL_FORMAT_YV12:
> >>> -      return DRM_FORMAT_YVU420;
> >>
> >> I'm not sure I understand the rationale for removing YVU420.
> >
> > Mostly its on Alexandru's suggestion, as I don't have any experience
> > w/ using YVU420.  Per his suggestion, my sense was that since its a
> > multi-plane format it was expected to fail with drmModeAddFB2().
> >
> > If that's incorrect, I'm fine with dropping this change.
> 
> drmModeAddFB2 absolutely works with multi-planar formats. I have no
> idea about the internals of HWC or why multi-planar formats aren't
> supported there though.
>
drmModeAddFb2 is fine, it definitely works if you pass the right data to it.
Which I don't think ImportBuffer does for DRM_FORMAT_YVU420, it
populates just one buffer handle. 

> Cheers,
> Daniel

Regards,
Alex Gheorghe