Re: Writeback Assumptions for XRGB

On Fri, 4 Mar 2022 15:46:07 +0100 Maxime Ripard maxime@cerno.tech wrote:

Indeed, while the input buffer uses 0xff for the X component, we'll get back 0x00 from the hardware, and thus the hashes are not identical. We can force the hardware to always set it to 0xff, but that doesn't seem right. It would make more sense to ignore the X component entirely in that case.

Hi,

I tried hard to send a slightly longer response, but gmail refuses to deliver to anyone without explanation. So here's a summary of my opinion:

- KMS must ignore X channel contents on read - IGT must ignore X channel contents when comparing results - it would be nice if IGT filled image X channels with garbage to verify the first two points

Thanks, pq