This patch partially reverts commit 36ec8f877481449bdfa072e6adf2060869e2b970 for IvyBridge CPUs.
The original commit results in repeated 'Timed out waiting for forcewake old ack to clear' messages on a Supermicro C7H61 board (BIOS version 2.00 and 2.00b) with i7-3770K CPU. It ultimately results in a hangup if the system is highly loaded. Reverting the commit for IvyBridge CPUs fixes the issue. Issue a warning if the CPU is IvyBridge and mt forcewake is disabled, since this condition can result in secondary issues. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=60541 Cc: Jesse Barnes <jbar...@virtuousgeek.org> Cc: Daniel Vetter <daniel.vet...@ffwll.ch> Cc: Mika Kuoppala <mika.kuopp...@intel.com> Signed-off-by: Guenter Roeck <li...@roeck-us.net> --- v2: Only revert patch for Ivybridge CPUs Issue info message if mt forcewake is disabled on Ivybridge drivers/gpu/drm/i915/intel_pm.c | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index aa01128..0392c28 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -4510,9 +4510,38 @@ 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)) { + u32 ecobus; + + /* IVB configs may use multi-threaded forcewake */ + + /* 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) { + 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 { + DRM_INFO("No MT forcewake available on Ivybridge, this can result in issues\n"); + DRM_INFO("when using vblank-synced partial screen updates.\n"); + 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; -- 1.7.9.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
