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drm/amdgpu/mst: Stop ignoring error codes and deadlocking

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It appears that amdgpu makes the mistake of completely ignoring the return
values from the DP MST helpers, and instead just returns a simple
true/false. In this case, it seems to have come back to bite us because as
a result of simply returning false from
compute_mst_dsc_configs_for_state(), amdgpu had no way of telling when a
deadlock happened from these helpers. This could definitely result in some
kernel splats.

V2:
* Address Wayne's comments (fix another bunch of spots where we weren't
  passing down return codes)

Signed-off-by: Lyude Paul <lyude@redhat.com>
Fixes: 8c20a1ed9b ("drm/amd/display: MST DSC compute fair share")
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: <stable@vger.kernel.org> # v5.6+
Reviewed-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Lyude Paul
2022-11-14 17:17:52 -05:00
committed by Alex Deucher
parent c6023d73a3
commit 7cce4cd628
3 changed files with 147 additions and 118 deletions
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18
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
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@@ -6539,7 +6539,7 @@ static int dm_update_mst_vcpi_slots_for_dsc(struct drm_atomic_state *state,
struct drm_connector_state *new_con_state;
struct amdgpu_dm_connector *aconnector;
struct dm_connector_state *dm_conn_state;
int i, j;
int i, j, ret;
int vcpi, pbn_div, pbn, slot_num = 0;
for_each_new_connector_in_state(state, connector, new_con_state, i) {
@@ -6586,8 +6586,11 @@ static int dm_update_mst_vcpi_slots_for_dsc(struct drm_atomic_state *state,
dm_conn_state->pbn = pbn;
dm_conn_state->vcpi_slots = slot_num;
drm_dp_mst_atomic_enable_dsc(state, aconnector->port, dm_conn_state->pbn,
false);
ret = drm_dp_mst_atomic_enable_dsc(state, aconnector->port,
dm_conn_state->pbn, false);
if (ret < 0)
return ret;
continue;
}
@@ -9604,10 +9607,9 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
#if defined(CONFIG_DRM_AMD_DC_DCN)
if (dc_resource_is_dsc_encoding_supported(dc)) {
if (!pre_validate_dsc(state, &dm_state, vars)) {
ret = -EINVAL;
ret = pre_validate_dsc(state, &dm_state, vars);
if (ret != 0)
goto fail;
}
}
#endif
@@ -9702,9 +9704,9 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
}
#if defined(CONFIG_DRM_AMD_DC_DCN)
if (!compute_mst_dsc_configs_for_state(state, dm_state->context, vars)) {
ret = compute_mst_dsc_configs_for_state(state, dm_state->context, vars);
if (ret) {
DRM_DEBUG_DRIVER("compute_mst_dsc_configs_for_state() failed\n");
ret = -EINVAL;
goto fail;
}