linux-kernel - [PATCH 5.14 019/151] drm/i915: Extend the async flip VT-d w/a to skl/bxt

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Date:   Mon, 11 Oct 2021 15:44:51 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Karthik B S <karthik.b.s@...el.com>,
        Ville Syrjälä 
        <ville.syrjala@...ux.intel.com>,
        Matt Roper <matthew.d.roper@...el.com>,
        Jani Nikula <jani.nikula@...el.com>
Subject: [PATCH 5.14 019/151] drm/i915: Extend the async flip VT-d w/a to skl/bxt

From: Ville Syrjälä <ville.syrjala@...ux.intel.com>

commit b2d73debfdc16b742e64948dc4461876af3f8c10 upstream.

Looks like skl/bxt/derivatives also need the plane stride
stretch w/a when using async flips and VT-d is enabled, or
else we get corruption on screen. To my surprise this was
even documented in bspec, but only as a note on the
CHICHKEN_PIPESL register description rather than on the
w/a list.

So very much the same thing as on HSW/BDW, except the bits
moved yet again.

Cc: stable@...r.kernel.org
Cc: Karthik B S <karthik.b.s@...el.com>
Fixes: 55ea1cb178ef ("drm/i915: Enable async flips in i915")
Signed-off-by: Ville Syrjälä <ville.syrjala@...ux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210930190943.17547-1-ville.syrjala@linux.intel.com
Reviewed-by: Matt Roper <matthew.d.roper@...el.com>
(cherry picked from commit d08df3b0bdb25546e86dc9a6c4e3ec0c43832299)
Signed-off-by: Jani Nikula <jani.nikula@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/gpu/drm/i915/i915_reg.h |    5 +++++
 drivers/gpu/drm/i915/intel_pm.c |   12 ++++++++++++
 2 files changed, 17 insertions(+)

--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -8150,6 +8150,11 @@ enum {
 #define  HSW_SPR_STRETCH_MAX_X1		REG_FIELD_PREP(HSW_SPR_STRETCH_MAX_MASK, 3)
 #define  HSW_FBCQ_DIS			(1 << 22)
 #define  BDW_DPRS_MASK_VBLANK_SRD	(1 << 0)
+#define  SKL_PLANE1_STRETCH_MAX_MASK	REG_GENMASK(1, 0)
+#define  SKL_PLANE1_STRETCH_MAX_X8	REG_FIELD_PREP(SKL_PLANE1_STRETCH_MAX_MASK, 0)
+#define  SKL_PLANE1_STRETCH_MAX_X4	REG_FIELD_PREP(SKL_PLANE1_STRETCH_MAX_MASK, 1)
+#define  SKL_PLANE1_STRETCH_MAX_X2	REG_FIELD_PREP(SKL_PLANE1_STRETCH_MAX_MASK, 2)
+#define  SKL_PLANE1_STRETCH_MAX_X1	REG_FIELD_PREP(SKL_PLANE1_STRETCH_MAX_MASK, 3)
 #define CHICKEN_PIPESL_1(pipe) _MMIO_PIPE(pipe, _CHICKEN_PIPESL_1_A, _CHICKEN_PIPESL_1_B)
 
 #define _CHICKEN_TRANS_A	0x420c0
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -76,6 +76,8 @@ struct intel_wm_config {
 
 static void gen9_init_clock_gating(struct drm_i915_private *dev_priv)
 {
+	enum pipe pipe;
+
 	if (HAS_LLC(dev_priv)) {
 		/*
 		 * WaCompressedResourceDisplayNewHashMode:skl,kbl
@@ -89,6 +91,16 @@ static void gen9_init_clock_gating(struc
 			   SKL_DE_COMPRESSED_HASH_MODE);
 	}
 
+	for_each_pipe(dev_priv, pipe) {
+		/*
+		 * "Plane N strech max must be programmed to 11b (x1)
+		 *  when Async flips are enabled on that plane."
+		 */
+		if (!IS_GEMINILAKE(dev_priv) && intel_vtd_active())
+			intel_uncore_rmw(&dev_priv->uncore, CHICKEN_PIPESL_1(pipe),
+					 SKL_PLANE1_STRETCH_MAX_MASK, SKL_PLANE1_STRETCH_MAX_X1);
+	}
+
 	/* See Bspec note for PSR2_CTL bit 31, Wa#828:skl,bxt,kbl,cfl */
 	intel_uncore_write(&dev_priv->uncore, CHICKEN_PAR1_1,
 		   intel_uncore_read(&dev_priv->uncore, CHICKEN_PAR1_1) | SKL_EDP_PSR_FIX_RDWRAP);