From: Nicholas Kazlauskas nicholas.kazlauskas@amd.com

[Why] Found when running igt@kms_atomic.

Userspace attempts to do a TEST_COMMIT when 0 streams which calls dc_remove_stream_from_ctx. This in turn calls link_enc_unassign which ends up modifying stream->link = NULL directly, causing the global link_enc to be removed preventing further link activity and future link validation from passing.

[How] We take care of link_enc unassignment at the start of link_enc_cfg_link_encs_assign so this call is no longer necessary.

Fixes global state from being modified while unlocked.

Reviewed-by: Jimmy Kizito Jimmy.Kizito@amd.com Acked-by: Jasdeep Dhillon jdhillon@amd.com Signed-off-by: Nicholas Kazlauskas nicholas.kazlauskas@amd.com Tested-by: Daniel Wheeler daniel.wheeler@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Cc: stable@vger.kernel.org (cherry picked from commit 3743e7f6fcb938b7d8b7967e6a9442805e269b3d) --- Please apply this for 5.15.y. This was already targeted to stable and 5.16.y picked it up but doesn't apply cleanly on 5.15.y. This problem exists in 5.15 as well but the nearby `#if defined(CONFIG_DRM_AMD_DC_DCN)` from DP 2.0 support hasn't been introduced in 5.15.y.

drivers/gpu/drm/amd/display/dc/core/dc_resource.c | 3 --- 1 file changed, 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c index e94546187cf1..7ae409f7dcf8 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c @@ -1799,9 +1799,6 @@ enum dc_status dc_remove_stream_from_ctx( dc->res_pool, del_pipe->stream_res.stream_enc, false); - /* Release link encoder from stream in new dc_state. */ - if (dc->res_pool->funcs->link_enc_unassign) - dc->res_pool->funcs->link_enc_unassign(new_ctx, del_pipe->stream);

if (del_pipe->stream_res.audio) update_audio_usage(