[Intel-gfx] [PATCH] drm/i915: Fix CHV data lane soft reset for HDMI

[Ander Conselvan de Oliveira]

The function chv_data_lane_soft_reset() uses the lane count to decide
which lanes to set/reset. However, the HDMI code never sets lane count,
since it always uses the four lanes of the phy. Note that before commit
a8f327fb8464 ("drm/i915: Clean up CHV lane soft reset programming"), all
lanes were reset, regardless of lane count, so this patch restores that
behavior.

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Deepak S <deepak.s at linux.intel.com>
Fixes: a8f327fb8464 ("drm/i915: Clean up CHV lane soft reset programming")
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira at intel.com>
---

I noticed this while reading CHV code, so this is only compiled tested. I
don't know if this could cause real issues.

Ander

---
 drivers/gpu/drm/i915/intel_hdmi.c | 30 +++++++++++++-----------------
 1 file changed, 13 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index b199ede..5410d1a 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1670,14 +1670,12 @@ static void chv_data_lane_soft_reset(struct intel_encoder *encoder,
 		val |= DPIO_PCS_TX_LANE2_RESET | DPIO_PCS_TX_LANE1_RESET;
 	vlv_dpio_write(dev_priv, pipe, VLV_PCS01_DW0(ch), val);
 
-	if (crtc->config->lane_count > 2) {
-		val = vlv_dpio_read(dev_priv, pipe, VLV_PCS23_DW0(ch));
-		if (reset)
-			val &= ~(DPIO_PCS_TX_LANE2_RESET | DPIO_PCS_TX_LANE1_RESET);
-		else
-			val |= DPIO_PCS_TX_LANE2_RESET | DPIO_PCS_TX_LANE1_RESET;
-		vlv_dpio_write(dev_priv, pipe, VLV_PCS23_DW0(ch), val);
-	}
+	val = vlv_dpio_read(dev_priv, pipe, VLV_PCS23_DW0(ch));
+	if (reset)
+		val &= ~(DPIO_PCS_TX_LANE2_RESET | DPIO_PCS_TX_LANE1_RESET);
+	else
+		val |= DPIO_PCS_TX_LANE2_RESET | DPIO_PCS_TX_LANE1_RESET;
+	vlv_dpio_write(dev_priv, pipe, VLV_PCS23_DW0(ch), val);
 
 	val = vlv_dpio_read(dev_priv, pipe, VLV_PCS01_DW1(ch));
 	val |= CHV_PCS_REQ_SOFTRESET_EN;
@@ -1687,15 +1685,13 @@ static void chv_data_lane_soft_reset(struct intel_encoder *encoder,
 		val |= DPIO_PCS_CLK_SOFT_RESET;
 	vlv_dpio_write(dev_priv, pipe, VLV_PCS01_DW1(ch), val);
 
-	if (crtc->config->lane_count > 2) {
-		val = vlv_dpio_read(dev_priv, pipe, VLV_PCS23_DW1(ch));
-		val |= CHV_PCS_REQ_SOFTRESET_EN;
-		if (reset)
-			val &= ~DPIO_PCS_CLK_SOFT_RESET;
-		else
-			val |= DPIO_PCS_CLK_SOFT_RESET;
-		vlv_dpio_write(dev_priv, pipe, VLV_PCS23_DW1(ch), val);
-	}
+	val = vlv_dpio_read(dev_priv, pipe, VLV_PCS23_DW1(ch));
+	val |= CHV_PCS_REQ_SOFTRESET_EN;
+	if (reset)
+		val &= ~DPIO_PCS_CLK_SOFT_RESET;
+	else
+		val |= DPIO_PCS_CLK_SOFT_RESET;
+	vlv_dpio_write(dev_priv, pipe, VLV_PCS23_DW1(ch), val);
 }
 
 static void chv_hdmi_pre_pll_enable(struct intel_encoder *encoder)
-- 
2.4.11