[Intel-gfx] [PATCH 2/2] drm/i915: save/restore fence registers across suspend/resume

[Keith Packard]

This makes software fallbacks not do tiling wrong on i965 and later after
resume. It also should fix 945 performance reduction after resume which
would have disabled tiling without causing any visible effect.

Signed-off-by: Keith Packard <keithp at keithp.com>
---
 drivers/gpu/drm/i915/i915_drv.h     |    1 +
 drivers/gpu/drm/i915/i915_suspend.c |   24 ++++++++++++++++++++++++
 2 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index df08eb4..b47af07 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -283,6 +283,7 @@ typedef struct drm_i915_private {
 	u8 saveAR[21];
 	u8 saveDACMASK;
 	u8 saveCR[37];
+	uint64_t saveFENCE[16];
 
 	struct {
 		struct drm_mm gtt_space;
diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c
index d669cc2..8727894 100644
--- a/drivers/gpu/drm/i915/i915_suspend.c
+++ b/drivers/gpu/drm/i915/i915_suspend.c
@@ -349,6 +349,18 @@ int i915_save_state(struct drm_device *dev)
 	for (i = 0; i < 3; i++)
 		dev_priv->saveSWF2[i] = I915_READ(SWF30 + (i << 2));
 
+	/* Fences */
+	if (IS_I965G(dev)) {
+		for (i = 0; i < 16; i++)
+			dev_priv->saveFENCE[i] = I915_READ64(FENCE_REG_965_0 + (i * 8));
+	} else {
+		for (i = 0; i < 8; i++)
+			dev_priv->saveFENCE[i] = I915_READ(FENCE_REG_830_0 + (i * 4));
+
+		if (IS_I9XX(dev))
+			for (i = 0; i < 8; i++)
+				dev_priv->saveFENCE[i+8] = I915_READ(FENCE_REG_945_8 + (i * 4));
+	}
 	i915_save_vga(dev);
 
 	return 0;
@@ -371,6 +383,18 @@ int i915_restore_state(struct drm_device *dev)
 	/* Display arbitration */
 	I915_WRITE(DSPARB, dev_priv->saveDSPARB);
 
+	/* Fences */
+	if (IS_I965G(dev)) {
+		for (i = 0; i < 16; i++)
+			I915_WRITE64(FENCE_REG_965_0 + (i * 8), dev_priv->saveFENCE[i]);
+	} else {
+		for (i = 0; i < 8; i++)
+			I915_WRITE(FENCE_REG_830_0 + (i * 4), dev_priv->saveFENCE[i]);
+		if (IS_I9XX(dev))
+			for (i = 0; i < 8; i++)
+				I915_WRITE(FENCE_REG_945_8 + (i * 4), dev_priv->saveFENCE[i+8]);
+	}
+	
 	/* Pipe & plane A info */
 	/* Prime the clock */
 	if (dev_priv->saveDPLL_A & DPLL_VCO_ENABLE) {
-- 
1.6.2.4