Some IVB machines seem to need non-MT forcewake. Using MT forcewake
on such machines result in broken or blank screens.
Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
The commit 36ec8f877481449bdfa072e6adf2060869e2b970 triggered a
regression on my test IVY laptops. Instead of reverting the commit,
I cooked a bit to make fitting only for IS_IVYBRIDGE().
drivers/gpu/drm/i915/intel_pm.c | 29 ++++++++++++++++++++++++++++-
1 file changed, 28 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 0cbc0e6..944911e 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4239,9 +4239,36 @@ void intel_gt_init(struct drm_device *dev)
if (IS_VALLEYVIEW(dev)) {
dev_priv->gt.force_wake_get = vlv_force_wake_get;
dev_priv->gt.force_wake_put = vlv_force_wake_put;
- } else if (IS_IVYBRIDGE(dev) || IS_HASWELL(dev)) {
+ } else if (IS_HASWELL(dev)) {
dev_priv->gt.force_wake_get = __gen6_gt_force_wake_mt_get;
dev_priv->gt.force_wake_put = __gen6_gt_force_wake_mt_put;
+ } else if (IS_IVYBRIDGE(dev)) {
+ /* IVB configs may use multi-threaded forcewake */
+ u32 ecobus;
+
+ /* A small trick here - if the bios hasn't configured
+ * MT forcewake, and if the device is in RC6, then
+ * force_wake_mt_get will not wake the device and the
+ * ECOBUS read will return zero. Which will be
+ * (correctly) interpreted by the test below as MT
+ * forcewake being disabled.
+ */
+ mutex_lock(&dev->struct_mutex);
+ __gen6_gt_force_wake_mt_get(dev_priv);
+ ecobus = I915_READ_NOTRACE(ECOBUS);
+ __gen6_gt_force_wake_mt_put(dev_priv);
+ mutex_unlock(&dev->struct_mutex);
+
+ if (ecobus & FORCEWAKE_MT_ENABLE) {
+ DRM_DEBUG_KMS("Using MT version of forcewake\n");
+ dev_priv->gt.force_wake_get =
+ __gen6_gt_force_wake_mt_get;
+ dev_priv->gt.force_wake_put =
+ __gen6_gt_force_wake_mt_put;
+ } else {
+ dev_priv->gt.force_wake_get = __gen6_gt_force_wake_get;
+ dev_priv->gt.force_wake_put = __gen6_gt_force_wake_put;
+ }
} else if (IS_GEN6(dev)) {
dev_priv->gt.force_wake_get = __gen6_gt_force_wake_get;
dev_priv->gt.force_wake_put = __gen6_gt_force_wake_put;
--
1.8.0
