drm/i915: vlv: reserve GT power context early

We reserve the space for the power context in stolen memory at a fixed
address from a delayed work. This races with the subsequent driver
init/resume code which could allocate something at that address, so the
reservation for the power context fails. Reserve the space up-front, so
this can't happen. This also adds a missing struct_mutex lock around the
stolen allocation, which wasn't taken in the delayed work path.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: stable@vger.kernel.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index d77cc81..e1fc35a 100644 (file)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3493,6 +3493,8 @@ static void valleyview_setup_pctx(struct drm_device *dev)
        u32 pcbr;
        int pctx_size = 24*1024;
 
+       WARN_ON(!mutex_is_locked(&dev->struct_mutex));
+
        pcbr = I915_READ(VLV_PCBR);
        if (pcbr) {
                /* BIOS set it up already, grab the pre-alloc'd space */
@@ -3542,8 +3544,6 @@ static void valleyview_enable_rps(struct drm_device *dev)
                I915_WRITE(GTFIFODBG, gtfifodbg);
        }
 
-       valleyview_setup_pctx(dev);
-
        /* If VLV, Forcewake all wells, else re-direct to regular path */
        gen6_gt_force_wake_get(dev_priv, FORCEWAKE_ALL);
 
@@ -4395,6 +4395,8 @@ void intel_enable_gt_powersave(struct drm_device *dev)
                ironlake_enable_rc6(dev);
                intel_init_emon(dev);
        } else if (IS_GEN6(dev) || IS_GEN7(dev)) {
+               if (IS_VALLEYVIEW(dev))
+                       valleyview_setup_pctx(dev);
                /*
                 * PCU communication is slow and this doesn't need to be
                 * done at any specific time, so do this out of our fast path