FAILED: patch "[PATCH] drm/i915/vlv: remove wait for previous GFX clk disable" failed to apply to 4.1-stable tree

The patch below does not apply to the 4.1-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From: Jesse Barnes <[email protected]>
Date: Wed, 1 Apr 2015 14:22:58 -0700
Subject: [PATCH] drm/i915/vlv: remove wait for previous GFX clk disable
request

Looks like it was introduced in:

commit 650ad970a39f8b6164fe8613edc150f585315289

Author: Imre Deak <[email protected]>
Date:   Fri Apr 18 16:35:02 2014 +0300

drm/i915: vlv: factor out vlv_force_gfx_clock and check for pending force-of

but I'm not sure why. It has caused problems for us in the past (see 85250ddff7a6 "drm/i915/chv: Remove Wait for a previous gfx force-off" and 8d4eee9cd7a1 "drm/i915: vlv: increase timeout when forcing on the GFX clock") and doesn't seem to be required, so let's just drop it.

References: https://bugs.freedesktop.org/show_bug.cgi?id=89611

[danvet: Repick this commit from 5df0582bf036bb5f9a8ad8db5884fe13a55347d1 becuase Dave Airlie lost it in his merge commit e1dee1973c74a0408b108d88c57a15be8a2d6d84.]

index 334bcc1badaa..6bb6c47db49f 100644
@@ -1286,21 +1286,7 @@ int vlv_force_gfx_clock(struct drm_i915_private *dev_priv, bool force_on)
 	u32 val;
 	int err;
 
-	val = I915_READ(VLV_GTLC_SURVIVABILITY_REG);
-
 #define COND (I915_READ(VLV_GTLC_SURVIVABILITY_REG) & VLV_GFX_CLK_STATUS_BIT)
-	/* Wait for a previous force-off to settle */
-	if (force_on && !IS_CHERRYVIEW(dev_priv->dev)) {
-		/* WARN_ON only for the Valleyview */
-		WARN_ON(!!(val & VLV_GFX_CLK_FORCE_ON_BIT) == force_on);
-
-		err = wait_for(!COND, 20);
-		if (err) {
-			DRM_ERROR("timeout waiting for GFX clock force-off (%08x)\n",
-				  I915_READ(VLV_GTLC_SURVIVABILITY_REG));
-			return err;
-		}
-	}
 
 	val = I915_READ(VLV_GTLC_SURVIVABILITY_REG);
 	val &= ~VLV_GFX_CLK_FORCE_ON_BIT;