[Intel-gfx] ✗ Fi.CI.BAT: failure for drm/i915: Enable WaProgramMgsrForCorrectSliceSpecificMmioReads for Gen9 (rev2)

[Chiou, Cooper]

> <3> [198.221812] [drm:wa_verify [i915]] *ERROR* engine workaround lost
> on application! (reg[b004]=0x0, relevant bits were 0x0 vs expected 0x80) <3>
> [198.222751] [drm:wa_verify [i915]] *ERROR* engine workaround lost on
> application! (reg[b118]=0x0, relevant bits were 0x0 vs expected 0x200000)
> <3> [198.223076] [drm:wa_verify [i915]] *ERROR* engine workaround lost
> on application! (reg[b11c]=0x0, relevant bits were 0x0 vs expected 0x4)
> 
> ?
> 
> CI does not think they are old warnings and registers are the MCR affected
> range. So more digging would be needed to be sure. You are saying those
> happen in our CI without the patch?

Hi Tvrtko,
This patch only programmed 0xfdc register in reg[fdc]=0x12000000, no touch 
reg[b004]=0x0 & reg[b118]=0x0 & reg[b11c]=0x0, so I don't think this error 
is caused by this change.
This error might be due to wa_write_masked_or() 

Meanwhile, as you can see this 2 kbl devices has different CI result.
1. fi-kbl-7500u - no any error log - 
https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_19752/fi-kbl-7500u/igt@gem_exec_suspend@basic-s0.html

2. fi-kbl-7567u- has register read/write error log: 
https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_19752/fi-kbl-7567u/igt@gem_exec_suspend@basic-s0.html

Cooper
> 
> Then with regards to the reported perf drop - something to check would be if
> the CML system you tested on has the same slice/subslice config as the one
> from which the original report originated. Might be hard if the test farm has
> been re-configured. But essentially running the benchmark on a few Gen9
> machine with fused ss would be needed I think.
> 
> And finally I couldn't find the WA entry in bspec, but maybe I just don't know
> where to look. Someone better versed to finding WA. Maybe Matt you would
> have time for a quick check if
> WaProgramMgsrForCorrectSliceSpecificMmioReads is documented as
> applicable to Gen9?
> 
> Regards,
> 
> Tvrtko