I admit up-front that this is ugly. This patch fixes fully reliable
hard-hang on my ilk when exercising the reset paths with the hangman
i-g-t tests. Both Chris Wilson and our QA couldn't reproduce this.
This regression has been introduced in
commit 1833b134454d5300d8a9d07b78876a20395f01a9
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date: Wed May 9 11:56:28 2012 +0100
drm/i915: gen6_enable_rps() wants to be called after ring initialisation
specifically calling intel_modeset_init_hw instead of open-coding half
of it. After some trial and error (and figuring out the hard way that
the problem only manifests after a full reboot) I've tracked it down
to calling ironlake_enable_drps.
Now I still think that having unified hw frobbing paths between driver
load, resume and gpu reset is highly desirable, so I've opted to just
add a reset argument to disable the offending code for gpu resets. I
have no idea why it actually blows up.
Signed-Off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
drivers/gpu/drm/i915/i915_drv.c | 4 ++--
drivers/gpu/drm/i915/i915_drv.h | 2 +-
drivers/gpu/drm/i915/intel_display.c | 9 ++++++---
3 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 238a521..d05fe30 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -640,7 +640,7 @@ static int i915_drm_thaw(struct drm_device *dev)
error = i915_gem_init_hw(dev);
mutex_unlock(&dev->struct_mutex);
- intel_modeset_init_hw(dev);
+ intel_modeset_init_hw(dev, false);
drm_mode_config_reset(dev);
drm_irq_install(dev);
@@ -908,7 +908,7 @@ int i915_reset(struct drm_device *dev)
mutex_unlock(&dev->struct_mutex);
if (drm_core_check_feature(dev, DRIVER_MODESET))
- intel_modeset_init_hw(dev);
+ intel_modeset_init_hw(dev, true);
drm_irq_uninstall(dev);
drm_irq_install(dev);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index ae4129b..04ad9c0 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1471,7 +1471,7 @@ static inline void intel_unregister_dsm_handler(void) { return; }
#endif /* CONFIG_ACPI */
/* modesetting */
-extern void intel_modeset_init_hw(struct drm_device *dev);
+extern void intel_modeset_init_hw(struct drm_device *dev, bool reset);
extern void intel_modeset_init(struct drm_device *dev);
extern void intel_modeset_gem_init(struct drm_device *dev);
extern void intel_modeset_cleanup(struct drm_device *dev);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 308e1a2..e76d12c 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6900,14 +6900,17 @@ static void ivb_pch_pwm_override(struct drm_device *dev)
I915_WRITE(BLC_PWM_PCH_CTL1, BLM_PCH_PWM_ENABLE | BLM_PCH_OVERRIDE_ENABLE);
}
-void intel_modeset_init_hw(struct drm_device *dev)
+void intel_modeset_init_hw(struct drm_device *dev, bool reset)
{
struct drm_i915_private *dev_priv = dev->dev_private;
intel_init_clock_gating(dev);
if (IS_IRONLAKE_M(dev)) {
- ironlake_enable_drps(dev);
+ /* Re-enabling drps on gpu reset hard-hangs some ilks for no
+ * apparent reason. Hence avoid it. */
+ if (!reset)
+ ironlake_enable_drps(dev);
ironlake_enable_rc6(dev);
intel_init_emon(dev);
}
@@ -6979,7 +6982,7 @@ void intel_modeset_init(struct drm_device *dev)
void intel_modeset_gem_init(struct drm_device *dev)
{
- intel_modeset_init_hw(dev);
+ intel_modeset_init_hw(dev, false);
intel_setup_overlay(dev);
}
--
1.7.7.6
