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Commit dfaf37ba authored by Rodrigo Vivi's avatar Rodrigo Vivi
Browse files

drm/i915: Fix idle_frames counter. 



'commit 97173eaf ("drm/i915: PSR: Increase idle_frames")' was a mistake.
The special case it tried to cover was already being covered by
the DP_PSR_NO_TRAIN_ON_EXIT. So this ended up duplicated.

So, instead of reverting that let's take this opportunity and unify
the idle_frame definition in a single place so we standardize the access
and avoid room for that same mistake again.

Few changes with this patch:

1. Instead of just respecting the VBT we set a
global minumum with max(). So we are sure that we will avoid corner cases
in case VBT is doing something we don't understand.

2. Instead of minimum 5 we use 6. When introducing the idle_frames += 4 case
we considered that minimum was 2. All because the off-by-one issue.

v2: Unified idle_frame definition.

Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: default avatarPaulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1449528320-27655-1-git-send-email-rodrigo.vivi@intel.com
parent 0d014ff3

drivers/gpu/drm/i915/intel_psr.c

+7 −13
Original line number Diff line number Diff line
@@ -267,23 +267,17 @@ static void hsw_psr_enable_source(struct intel_dp *intel_dp) 
	struct drm_i915_private *dev_priv = dev->dev_private;



	uint32_t max_sleep_time = 0x1f;

	/* Lately it was identified that depending on panel idle frame count

	 * calculated at HW can be off by 1. So let's use what came

	 * from VBT + 1.

	 * There are also other cases where panel demands at least 4

	 * but VBT is not being set. To cover these 2 cases lets use

	 * at least 5 when VBT isn't set to be on the safest side.

	/*

	 * Let's respect VBT in case VBT asks a higher idle_frame value.

	 * Let's use 6 as the minimum to cover all known cases including

	 * the off-by-one issue that HW has in some cases. Also there are

	 * cases where sink should be able to train

	 * with the 5 or 6 idle patterns.

	 */

	uint32_t idle_frames = dev_priv->vbt.psr.idle_frames ?

			       dev_priv->vbt.psr.idle_frames + 1 : 5;

	uint32_t idle_frames = max(6, dev_priv->vbt.psr.idle_frames);

	uint32_t val = 0x0;

	const uint32_t link_entry_time = EDP_PSR_MIN_LINK_ENTRY_TIME_8_LINES;



	if (intel_dp->psr_dpcd[1] & DP_PSR_NO_TRAIN_ON_EXIT) {

		/* Sink should be able to train with the 5 or 6 idle patterns */

		idle_frames += 4;

	}



	I915_WRITE(EDP_PSR_CTL, val |

		   (IS_BROADWELL(dev) ? 0 : link_entry_time) |

		   max_sleep_time << EDP_PSR_MAX_SLEEP_TIME_SHIFT |