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From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
	Arthur Ranyan <arthur.j.runyan@intel.com>
Subject: [PATCH 3/5] drm/i915: CPT/PPT pch transcoder workaround
Date: Wed, 31 Oct 2012 22:52:29 +0100
Message-ID: <1351720351-2688-4-git-send-email-daniel.vetter@ffwll.ch> (raw)
In-Reply-To: <1351720351-2688-1-git-send-email-daniel.vetter@ffwll.ch>

We need to set the timing override chicken bit after fdi link training
has completed and before we enable the transcoder. We also have to
clear that bit again after disabling the pch transcoder.

See "Graphics BSpec: vol4g North Display Engine Registers [IVB],
Display Mode Set Sequence" and "Graphics BSpec: vol4h South Display
Engine Registers [CPT, PPT], South Display Engine Transcoder and FDI
Control, Transcoder Debug and DFT, TRANS_CHICKEN_2" bit 31:

"Workaround : Enable the override prior to enabling the transcoder.
Disable the override after disabling the transcoder."

While at it, use the _PIPE macro for the other TRANS_DP register.

v2: Keep the w/a as-is, but kill the original (but wrongly placed)
workaround introduced in

commit 3bcf603f6d5d18bd9d076dc280de71f48add4101
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Wed Jul 27 11:51:40 2011 -0700

    drm/i915: apply timing generator bug workaround on CPT and PPT

and

commit d4270e57efe9e2536798c59e1ed2fd0a1e5cdfcf
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Tue Oct 11 10:43:02 2011 -0700

    drm/i915: export a CPT mode set verification function

Note that this old code has unconditionally set the w/a, which might
explain why fdi link training sometimes silently fails, and especially
why the auto-train did not seem to work properly.

v3: Paulo Zanoni pointed out that this workaround is also required on
the LPT PCH. And Arthur Ranyan confirmed that this workaround is
requierd for all ports on the pch, not just DP: The important part
is that the bit is set whenever the pch transcoder is enabled, and
that it is _not_ set while the fdi link is trained. It is also
important that the pch transcoder is fully disabled, i.e. we have to
wait for bit 30 to clear before clearing the w/a bit.

Hence move to workaround into enable/disable_transcoder, where the pch
transcoder gets enabled/disabled.

v4: Whitespace changes dropped.

Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Paulo Zanoni <przanoni@gmail.com>
Cc: Arthur Ranyan <arthur.j.runyan@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/i915/i915_reg.h      |  5 +++--
 drivers/gpu/drm/i915/intel_display.c | 26 +++++++++++++++++---------
 drivers/gpu/drm/i915/intel_pm.c      |  4 ----
 3 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 2dd880f..f1fe3a0 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3806,7 +3806,8 @@
 #define _TRANSA_CHICKEN2	 0xf0064
 #define _TRANSB_CHICKEN2	 0xf1064
 #define TRANS_CHICKEN2(pipe) _PIPE(pipe, _TRANSA_CHICKEN2, _TRANSB_CHICKEN2)
-#define   TRANS_AUTOTRAIN_GEN_STALL_DIS	(1<<31)
+#define  TRANS_CHICKEN2_TIMING_OVERRIDE		(1<<31)
+
 
 #define SOUTH_CHICKEN1		0xc2000
 #define  FDIA_PHASE_SYNC_SHIFT_OVR	19
@@ -4064,7 +4065,7 @@
 #define TRANS_DP_CTL_A		0xe0300
 #define TRANS_DP_CTL_B		0xe1300
 #define TRANS_DP_CTL_C		0xe2300
-#define TRANS_DP_CTL(pipe)	(TRANS_DP_CTL_A + (pipe) * 0x01000)
+#define TRANS_DP_CTL(pipe)	_PIPE(pipe, TRANS_DP_CTL_A, TRANS_DP_CTL_B)
 #define  TRANS_DP_OUTPUT_ENABLE	(1<<31)
 #define  TRANS_DP_PORT_SEL_B	(0<<29)
 #define  TRANS_DP_PORT_SEL_C	(1<<29)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 129059b..d27d683 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1673,8 +1673,7 @@ static void intel_disable_pch_pll(struct intel_crtc *intel_crtc)
 static void intel_enable_transcoder(struct drm_i915_private *dev_priv,
 				    enum pipe pipe)
 {
-	int reg;
-	u32 val, pipeconf_val;
+	uint32_t reg, val, pipeconf_val;
 	struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
 
 	/* PCH only available on ILK+ */
@@ -1693,6 +1692,14 @@ static void intel_enable_transcoder(struct drm_i915_private *dev_priv,
 		DRM_ERROR("Attempting to enable transcoder on Haswell with pipe > 0\n");
 		return;
 	}
+
+	/* Workaround: Set the timing override bit before enabling the
+	 * pch transcoder. */
+	reg = TRANS_CHICKEN2(pipe);
+	val = I915_READ(reg);
+	val |= TRANS_CHICKEN2_TIMING_OVERRIDE;
+	I915_WRITE(reg, val);
+
 	reg = TRANSCONF(pipe);
 	val = I915_READ(reg);
 	pipeconf_val = I915_READ(PIPECONF(pipe));
@@ -1724,8 +1731,7 @@ static void intel_enable_transcoder(struct drm_i915_private *dev_priv,
 static void intel_disable_transcoder(struct drm_i915_private *dev_priv,
 				     enum pipe pipe)
 {
-	int reg;
-	u32 val;
+	uint32_t reg, val;
 
 	/* FDI relies on the transcoder */
 	assert_fdi_tx_disabled(dev_priv, pipe);
@@ -1741,6 +1747,12 @@ static void intel_disable_transcoder(struct drm_i915_private *dev_priv,
 	/* wait for PCH transcoder off, transcoder state */
 	if (wait_for((I915_READ(reg) & TRANS_STATE_ENABLE) == 0, 50))
 		DRM_ERROR("failed to disable transcoder %d\n", pipe);
+
+	/* Workaround: Clear the timing override chicken bit again. */
+	reg = TRANS_CHICKEN2(pipe);
+	val = I915_READ(reg);
+	val &= ~TRANS_CHICKEN2_TIMING_OVERRIDE;
+	I915_WRITE(reg, val);
 }
 
 /**
@@ -3217,16 +3229,12 @@ prepare: /* separate function? */
 void intel_cpt_verify_modeset(struct drm_device *dev, int pipe)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	int dslreg = PIPEDSL(pipe), tc2reg = TRANS_CHICKEN2(pipe);
+	int dslreg = PIPEDSL(pipe);
 	u32 temp;
 
 	temp = I915_READ(dslreg);
 	udelay(500);
 	if (wait_for(I915_READ(dslreg) != temp, 5)) {
-		/* Without this, mode sets may fail silently on FDI */
-		I915_WRITE(tc2reg, TRANS_AUTOTRAIN_GEN_STALL_DIS);
-		udelay(250);
-		I915_WRITE(tc2reg, 0);
 		if (wait_for(I915_READ(dslreg) != temp, 5))
 			DRM_ERROR("mode set failed: pipe %d stuck\n", pipe);
 	}
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index a04b336..3469fbd 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3786,7 +3786,6 @@ static void ibx_init_clock_gating(struct drm_device *dev)
 static void cpt_init_clock_gating(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	int pipe;
 
 	/*
 	 * On Ibex Peak and Cougar Point, we need to disable clock
@@ -3796,9 +3795,6 @@ static void cpt_init_clock_gating(struct drm_device *dev)
 	I915_WRITE(SOUTH_DSPCLK_GATE_D, PCH_DPLSUNIT_CLOCK_GATE_DISABLE);
 	I915_WRITE(SOUTH_CHICKEN2, I915_READ(SOUTH_CHICKEN2) |
 		   DPLS_EDP_PPS_FIX_DIS);
-	/* Without this, mode sets may fail silently on FDI */
-	for_each_pipe(pipe)
-		I915_WRITE(TRANS_CHICKEN2(pipe), TRANS_AUTOTRAIN_GEN_STALL_DIS);
 }
 
 void intel_init_clock_gating(struct drm_device *dev)
-- 
1.7.11.4

  parent reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-31 21:52 [PATCH 0/5] ivb fdi b/c fixes Daniel Vetter
2012-10-31 21:52 ` [PATCH 1/5] drm/i915: check whether the pch is the soulmate of the cpu Daniel Vetter
2012-11-01 15:58   ` Paulo Zanoni
2012-10-31 21:52 ` [PATCH 2/5] drm/i915: drop unnecessary check from fdi_link_train code Daniel Vetter
2012-10-31 21:52 ` Daniel Vetter [this message]
2012-11-01  8:15   ` [PATCH] drm/i915: CPT/PPT pch dp transcoder workaround Daniel Vetter
2012-11-01 14:37     ` Jesse Barnes
2012-11-01 15:33       ` Daniel Vetter
2012-11-01 15:35         ` Jesse Barnes
2012-11-01 16:12     ` Paulo Zanoni
2012-10-31 21:52 ` [PATCH 4/5] drm/i915: implement WADP0ClockGatingDisable Daniel Vetter
2012-11-01 16:18   ` Paulo Zanoni
2012-10-31 21:52 ` [PATCH 5/5] drm/i915: kill pch_init_clock_gating indirection Daniel Vetter
2012-11-01 16:35   ` Paulo Zanoni
2012-11-01 22:03     ` Daniel Vetter

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