drm/i915/vlv: remove wait for previous GFX clk disable request

Looks like it was introduced in:

commit 650ad970a39f8b6164fe8613edc150f585315289
Author: Imre Deak <imre.deak@intel.com>
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
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: Darren Hart <dvhart@linux.intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Cc: stable@vger.kernel.org # c9c52e24194a: drm/i915/chv: Remove Wait ...
Cc: stable@vger.kernel.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 3fa3eae..5c66b56 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1199,21 +1199,7 @@ 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;