4.18-stable review patch. If anyone has any objections, please let me know.
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From: Harry Wentland harry.wentland@amd.com
commit 01dc285d5cd89b77686d8baef8482c58d7dc3ead upstream.
[Why] Some boards seem to have a problem where HPD is high on HDMI even though no display is connected. We don't want to report these as connected. DP spec still requires us to report DP displays as connected when HPD is high but we can't read the EDID in order to go to fail-safe mode.
[How] If connector_signal is not DP abort detection if we can't retrieve the EDID.
v2: Add Bugzilla and stable
Bugzilla: https://bugs.freedesktop.org/107390 Bugzilla: https://bugs.freedesktop.org/106846 Cc: stable@vger.kernel.org Signed-off-by: Harry Wentland harry.wentland@amd.com Acked-by: Alex Deucher alexander.deucher@amd.com Reviewed-by: Nicholas Kazlauskas nicholas.kazlauskas@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/amd/display/dc/core/dc_link.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c @@ -728,6 +728,17 @@ bool dc_link_detect(struct dc_link *link break; case EDID_NO_RESPONSE: DC_LOG_ERROR("No EDID read.\n"); + + /* + * Abort detection for non-DP connectors if we have + * no EDID + * + * DP needs to report as connected if HDP is high + * even if we have no EDID in order to go to + * fail-safe mode + */ + if (!dc_is_dp_signal(link->connector_signal)) + return false; default: break; }