i915: Save/restore MCHBAR_RENDER_STANDBY on GM965/GM45

This register is set by the 2D driver to prevent lockups, and so it needs to
be preserved across suspend/resume too. This makes my X200s work.

Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@linux.ie>

3 files changed, 13 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 572dcd0e3e0..be56b0ba88c 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -157,6 +157,7 @@ typedef struct drm_i915_private {
         u32 saveDSPACNTR;
         u32 saveDSPBCNTR;
         u32 saveDSPARB;
+        u32 saveRENDERSTANDBY;
         u32 savePIPEACONF;
         u32 savePIPEBCONF;
         u32 savePIPEASRC;
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 5c2d9f206d0..0e476eba36e 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -527,6 +527,9 @@
 #define C0DRB3                  0x10206
 #define C1DRB3                  0x10606
 
+/** GM965 GM45 render standby register */
+#define MCHBAR_RENDER_STANDBY   0x111B8
+
 /*
  * Overlay regs
  */
diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c
index 603fe742ccd..5ddc6e595c0 100644
--- a/drivers/gpu/drm/i915/i915_suspend.c
+++ b/drivers/gpu/drm/i915/i915_suspend.c
@@ -240,6 +240,10 @@ int i915_save_state(struct drm_device *dev)
 
         pci_read_config_byte(dev->pdev, LBB, &dev_priv->saveLBB);
 
+        /* Render Standby */
+        if (IS_I965G(dev) && IS_MOBILE(dev))
+                dev_priv->saveRENDERSTANDBY = I915_READ(MCHBAR_RENDER_STANDBY);
+
         /* Display arbitration control */
         dev_priv->saveDSPARB = I915_READ(DSPARB);
 
@@ -365,6 +369,11 @@ int i915_restore_state(struct drm_device *dev)
 
         pci_write_config_byte(dev->pdev, LBB, dev_priv->saveLBB);
 
+        /* Render Standby */
+        if (IS_I965G(dev) && IS_MOBILE(dev))
+                I915_WRITE(MCHBAR_RENDER_STANDBY, dev_priv->saveRENDERSTANDBY);
+
+        /* Display arbitration */
         I915_WRITE(DSPARB, dev_priv->saveDSPARB);
 
         /* Pipe & plane A info */