drm/i915/vlv: reset VLV media force wake request register

commit 05adaf1f101f25f40f12c29403e6488f0e45f6b6 upstream.

Media force wake get hangs the machine when the system is booted without
displays attached. The assumption is that (at least some versions of)
the firmware has skipped some initialization in that case.

Empirical evidence suggests we need to reset the media force wake
request register in addition to the render one to avoid hangs.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=75895
Reported-by: Imre Deak <imre.deak@intel.com>
Reported-by: Darren Hart <dvhart@linux.intel.com>
Tested-by: Darren Hart <dvhart@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index ee7d6491f8cd527842eacccb1583a246b8b14f7c..a9a015428b8b437cb0c23c318e1b642da022e004 100644 (file)
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -166,6 +166,8 @@ static void vlv_force_wake_reset(struct drm_i915_private *dev_priv)
 {
        __raw_i915_write32(dev_priv, FORCEWAKE_VLV,
                           _MASKED_BIT_DISABLE(0xffff));
+       __raw_i915_write32(dev_priv, FORCEWAKE_MEDIA_VLV,
+                          _MASKED_BIT_DISABLE(0xffff));
        /* something from same cacheline, but !FORCEWAKE_VLV */
        __raw_posting_read(dev_priv, FORCEWAKE_ACK_VLV);
 }