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Commit af8fcb9c authored by Clint Taylor's avatar Clint Taylor Committed by Jani Nikula
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drm/i915/chv: Remove DPIO force latency causing interpair skew issue 



Latest version of the "CHV DPIO programming notes" no longer requires writes
to TX DW 11 to fix a +2UI interpair skew issue. The current code from
April 2014 was actually causing additional skew issues between all
TMDS pairs.

ver2: added same treatment to intel_dp.c based on Ville's testing.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarClint Taylor <clinton.a.taylor@intel.com>
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
parent 88f933a8

drivers/gpu/drm/i915/intel_dp.c

+0 −5
Original line number Original line Diff line number Diff line
@@ -2742,11 +2742,6 @@ static void chv_pre_enable_dp(struct intel_encoder *encoder) 




	/* Program Tx lane latency optimal setting*/

	/* Program Tx lane latency optimal setting*/

	for (i = 0; i < 4; i++) {

	for (i = 0; i < 4; i++) {

		/* Set the latency optimal bit */

		data = (i == 1) ? 0x0 : 0x6;

		vlv_dpio_write(dev_priv, pipe, CHV_TX_DW11(ch, i),

				data << DPIO_FRC_LATENCY_SHFIT);



		/* Set the upar bit */

		/* Set the upar bit */

		data = (i == 1) ? 0x0 : 0x1;

		data = (i == 1) ? 0x0 : 0x1;

		vlv_dpio_write(dev_priv, pipe, CHV_TX_DW14(ch, i),

		vlv_dpio_write(dev_priv, pipe, CHV_TX_DW14(ch, i),

drivers/gpu/drm/i915/intel_hdmi.c

+0 −5
Original line number Original line Diff line number Diff line
@@ -1515,11 +1515,6 @@ static void chv_hdmi_pre_enable(struct intel_encoder *encoder) 




	/* Program Tx latency optimal setting */

	/* Program Tx latency optimal setting */

	for (i = 0; i < 4; i++) {

	for (i = 0; i < 4; i++) {

		/* Set the latency optimal bit */

		data = (i == 1) ? 0x0 : 0x6;

		vlv_dpio_write(dev_priv, pipe, CHV_TX_DW11(ch, i),

				data << DPIO_FRC_LATENCY_SHFIT);



		/* Set the upar bit */

		/* Set the upar bit */

		data = (i == 1) ? 0x0 : 0x1;

		data = (i == 1) ? 0x0 : 0x1;

		vlv_dpio_write(dev_priv, pipe, CHV_TX_DW14(ch, i),

		vlv_dpio_write(dev_priv, pipe, CHV_TX_DW14(ch, i),