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drm/amd/display: Fix deadlock when falling back to v2 from v3

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[Why]
A deadlock in the kernel occurs when we fallback from the V3 to V2
add_topology_to_display or remove_topology_to_display because they
both try to acquire the dtm_mutex but recursive locking isn't
supported on mutex_lock().

[How]
Make the mutex_lock/unlock more fine grained and move them up such that
they're only required for the psp invocation itself.

Fixes: bf62221e9d0e ("drm/amd/display: Add DCN3.1 HDCP support")

Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Aric Cyr <aric.cyr@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
This commit is contained in:
Nicholas Kazlauskas 2021-10-22 16:14:24 -04:00 committed by Alex Deucher
parent 54149d13f3
commit ad76744b04
1 changed files with 2 additions and 4 deletions
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6
drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c
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@ -105,6 +105,7 @@ static enum mod_hdcp_status remove_display_from_topology_v3(
dtm_cmd->dtm_status = TA_DTM_STATUS__GENERIC_FAILURE;
psp_dtm_invoke(psp, dtm_cmd->cmd_id);
mutex_unlock(&psp->dtm_context.mutex);
if (dtm_cmd->dtm_status != TA_DTM_STATUS__SUCCESS) {
status = remove_display_from_topology_v2(hdcp, index);
@ -115,8 +116,6 @@ static enum mod_hdcp_status remove_display_from_topology_v3(
HDCP_TOP_REMOVE_DISPLAY_TRACE(hdcp, display->index);
}
mutex_unlock(&psp->dtm_context.mutex);
return status;
}
@ -205,6 +204,7 @@ static enum mod_hdcp_status add_display_to_topology_v3(
dtm_cmd->dtm_in_message.topology_update_v3.link_hdcp_cap = link->hdcp_supported_informational;
psp_dtm_invoke(psp, dtm_cmd->cmd_id);
mutex_unlock(&psp->dtm_context.mutex);
if (dtm_cmd->dtm_status != TA_DTM_STATUS__SUCCESS) {
status = add_display_to_topology_v2(hdcp, display);
@ -214,8 +214,6 @@ static enum mod_hdcp_status add_display_to_topology_v3(
HDCP_TOP_ADD_DISPLAY_TRACE(hdcp, display->index);
}
mutex_unlock(&psp->dtm_context.mutex);
return status;
}