drm/amd/display: Determine IPS mode by ASIC and PMFW versions
[Why]
DCN IPS interoperates with other system idle power features, such as
Zstates.
On DCN35, there is a known issue where system Z8 + DCN IPS2 causes a
hard hang. We observe this on systems where the SBIOS allows Z8.
Though there is a SBIOS fix, there's no guarantee that users will get it
any time soon, or even install it. A workaround is needed to prevent
this from rearing its head in the wild.
[How]
For DCN35, check the pmfw version to determine whether the SBIOS has the
fix. If not, set IPS1+RCG as the deepest possible state in all cases
except for s0ix and display off (DPMS). Otherwise, enable all IPS
Signed-off-by: Leo Li <sunpeng.li@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
1 file changed
