[PATCH] drm/i915: Clear FORCEWAKE when taking over from BIOS

Chris Wilson
2012-10-18T10:47:23Z

Some BIOSes may forcibly suspend RC6 during their operation which
trigger a warning as we find the hardware in a perplexing state upon
first use. So far that appears to be the worst symptom as fortuituously
we use the same values as the BIOS for programming the FORCEWAKE register.

Reported-by: <bug-track@fisher-privat.net>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_drv.c | 2 ++
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/intel_pm.c | 32 ++++++++++++++++++++++++++++++++
3 files changed, 35 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 705b2e1..ea2b718 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -526,6 +526,8 @@ static int i915_drm_thaw(struct drm_device *dev)
struct drm_i915_private *dev_priv = dev->dev_private;
int error = 0;

+ intel_gt_reset(dev);
+
if (drm_core_check_feature(dev, DRIVER_MODESET)) {
mutex_lock(&dev->struct_mutex);
i915_gem_restore_gtt_mappings(dev);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 2b7f07b..3a0c102 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1300,6 +1300,7 @@ void i915_handle_error(struct drm_device *dev, bool wedged);

extern void intel_irq_init(struct drm_device *dev);
extern void intel_gt_init(struct drm_device *dev);
+extern void intel_gt_reset(struct drm_device *dev);

void i915_error_state_free(struct kref *error_ref);

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 423ee69..fbdb104 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3999,6 +3999,12 @@ static void __gen6_gt_wait_for_thread_c0(struct drm_i915_private *dev_priv)
DRM_ERROR("GT thread status wait timed out\n");
}

+static void __gen6_gt_force_wake_reset(struct drm_i915_private *dev_priv)
+{
+ I915_WRITE_NOTRACE(FORCEWAKE, 0);
+ POSTING_READ(ECOBUS); /* something from same cacheline, but !FORCEWAKE */
+}
+
static void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv)
{
u32 forcewake_ack;
@@ -4022,6 +4028,12 @@ static void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv)
__gen6_gt_wait_for_thread_c0(dev_priv);
}

+static void __gen6_gt_force_wake_mt_reset(struct drm_i915_private *dev_priv)
+{
+ I915_WRITE_NOTRACE(FORCEWAKE_MT, _MASKED_BIT_DISABLE(0xffff));
+ POSTING_READ(ECOBUS); /* something from same cacheline, but !FORCEWAKE */
+}
+
static void __gen6_gt_force_wake_mt_get(struct drm_i915_private *dev_priv)
{
u32 forcewake_ack;
@@ -4117,6 +4129,11 @@ int __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv)
return ret;
}

+static void vlv_force_wake_reset(struct drm_i915_private *dev_priv)
+{
+ I915_WRITE_NOTRACE(FORCEWAKE_VLV, _MASKED_BIT_DISABLE(0xffff));
+}
+
static void vlv_force_wake_get(struct drm_i915_private *dev_priv)
{
if (wait_for_atomic((I915_READ_NOTRACE(FORCEWAKE_ACK_VLV) & 1) == 0,
@@ -4139,12 +4156,27 @@ static void vlv_force_wake_put(struct drm_i915_private *dev_priv)
gen6_gt_check_fifodbg(dev_priv);
}

+void intel_gt_reset(struct drm_device *dev)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+
+ if (IS_VALLEYVIEW(dev)) {
+ vlv_force_wake_reset(dev_priv);
+ } else if (INTEL_INFO(dev)->gen >= 6) {
+ __gen6_gt_force_wake_reset(dev_priv);
+ if (IS_IVYBRIDGE(dev) || IS_HASWELL(dev))
+ __gen6_gt_force_wake_mt_reset(dev_priv);
+ }
+}
+
void intel_gt_init(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;

spin_lock_init(&dev_priv->gt_lock);

+ intel_gt_reset(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;
--
1.7.10.4