drm/amd/display: fix pipe selection logic in validate
authorJun Lei <Jun.Lei@amd.com>
Mon, 22 Jul 2019 13:45:20 +0000 (09:45 -0400)
committerAlex Deucher <alexander.deucher@amd.com>
Thu, 15 Aug 2019 15:55:04 +0000 (10:55 -0500)
commitc681491a09213e6675c773a04f1e8801ffc201ff
tree7325d9ceb706bcf0974bcc4d5f307e94e781b276
parent04cf85d2d9a2b177e8d3ee0a8a801ecf8fcf5666
drm/amd/display: fix pipe selection logic in validate

[why]
Resource mapping done in dcn20_validate_bandwidth has a flaw:  When a full
update is performed, the HWSS will only update the MPCC tree for the stream
that is updated as opposed to all streams.  This means that when mapping pipes
in validation, care must be taken to not change any existing mapping, otherwise it
leads to partial hw programming

[how]
it's not strictly necessary to track which stream/mpcc tree is being updated, but
rather it's sufficient to compare current and new state and just keep pipes that were
previously already mapped unchanged.

Signed-off-by: Jun Lei <Jun.Lei@amd.com>
Reviewed-by: Eric Yang <eric.yang2@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c