On Tue, 23 Feb 2021 at 14:58, Brian Starkey brian.starkey@arm.com wrote:
On Tue, Feb 23, 2021 at 02:27:11PM +0000, Daniel Stone wrote:
Mark, or others from Rockchip, can you please:
- explain if there is a way to enable/disable the YTR transform in the
VOP's AFBC decoder, similar to the split-block control bit?
- ack this patch which correctly declares that the YTR transform is in
use in order to make Panfrost work, so it can be merged through drm-misc, or provide another solution which fixes this API mistake?
- if VOP does have a hidden YTR-disable bit, add support to disable
YTR so rockchip-drm can continue advertising the non-YTR modifier, and Cc this patch for backporting to every kernel tree which declares AFBC modifier support?
Drive-by $0.02:
As described in https://www.kernel.org/doc/Documentation/gpu/afbc.rst, YTR is only valid for "BGR" component order, so this shouldn't be set or used for "RGB" order (or YUV) formats. For BGR-order formats, it's best to always enable YTR to get the best compression ratio.
In an ideal world, there wouldn't be hardware/drivers which support/allow non-standard encodings, but we don't live in that world :-(
This implies that RGB component ordering cannot be used together with AFBC on RK3399, no?
Cheers, Daniel