Commit fee50077 authored by Mario Limonciello's avatar Mario Limonciello Committed by Alex Deucher
Browse files

drm/amd/display: Bump the HDMI clock to 340MHz 



[Why]
DP-HDMI dongles can execeed bandwidth requirements on high resolution
monitors. This can lead to pruning the high resolution modes.

HDMI 1.3 bumped the clock to 340MHz, but display code never matched it.

[How]
Set default to (DVI) 165MHz.  Once HDMI display is identified update
to 340MHz.

Reported-by: default avatarDianne Skoll <dianne@skoll.ca>
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4780


Reviewed-by: default avatarChris Park <chris.park@amd.com>
Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Signed-off-by: default avatarMatthew Stewart <matthew.stewart2@amd.com>
Tested-by: default avatarDan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
(cherry picked from commit ac1e65d8)
Cc: stable@vger.kernel.org
parent 0a1253ba

drivers/gpu/drm/amd/display/dc/dc_hdmi_types.h

+1 −1
Original line number Diff line number Diff line
@@ -41,7 +41,7 @@ 
/* kHZ*/

#define DP_ADAPTOR_DVI_MAX_TMDS_CLK 165000

/* kHZ*/

#define DP_ADAPTOR_HDMI_SAFE_MAX_TMDS_CLK 165000

#define DP_ADAPTOR_HDMI_SAFE_MAX_TMDS_CLK 340000



struct dp_hdmi_dongle_signature_data {

	int8_t id[15];/* "DP-HDMI ADAPTOR"*/

drivers/gpu/drm/amd/display/dc/link/link_detection.c

+3 −1
Original line number Diff line number Diff line
@@ -336,7 +336,7 @@ static void query_dp_dual_mode_adaptor( 


	/* Assume we have no valid DP passive dongle connected */

	*dongle = DISPLAY_DONGLE_NONE;

	sink_cap->max_hdmi_pixel_clock = DP_ADAPTOR_HDMI_SAFE_MAX_TMDS_CLK;

	sink_cap->max_hdmi_pixel_clock = DP_ADAPTOR_DVI_MAX_TMDS_CLK;



	/* Read DP-HDMI dongle I2c (no response interpreted as DP-DVI dongle)*/

	if (!i2c_read(
@@ -392,6 +392,8 @@ static void query_dp_dual_mode_adaptor( 


		}

	}

	if (is_valid_hdmi_signature)

		sink_cap->max_hdmi_pixel_clock = DP_ADAPTOR_HDMI_SAFE_MAX_TMDS_CLK;



	if (is_type2_dongle) {

		uint32_t max_tmds_clk =