[Intel-gfx] Question about CCS modifier on GLK

[Gabriel Krisman Bertazi]

Hi Ben and list folks,

I've been investigating some CI failures with the kms_ccs testcase in
the GLK hardware.  The original bug is linked below, but there are other
more basic tests failing when trying CCS on pipe C.

https://bugs.freedesktop.org/show_bug.cgi?id=104096

The reason for the failure is very straightforward, the function
skl_check_ccs_aux_surface() in intel_display.c rejects CCS modifiers for
PIPE_C, since that is not supported for SKL, KBL and as far as I can
tell APL as well.

But, since I don't have the specs for GLK yet (it's not available in
01.org), I can't tell if GLK will support it and the kernel must be
changed or if the testcase itself is bogus.  My money is on the later,
but I could use a confirmation before writing down the patch.

In short, does pipe C support render compression (ccs modifier) in glk?

Thanks,

-- 
Gabriel Krisman Bertazi