From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jesse Barnes , Daniel Vetter , Mika Kuoppala , Guenter Roeck Subject: [ 75/99] Partially revert "drm/i915: unconditionally use mt forcewake on hsw/ivb" Date: Fri, 2 Aug 2013 18:08:28 +0800 Message-Id: <20130802100236.428324993@linuxfoundation.org> In-Reply-To: <20130802100225.478715166@linuxfoundation.org> References: <20130802100225.478715166@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Guenter Roeck commit c11e5f35ab490bd30591563816fbc83526521777 upstream. 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. v2: Only revert patch for Ivybridge CPUs Issue info message if mt forcewake is disabled on Ivybridge Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=60541 Cc: Jesse Barnes Cc: Daniel Vetter Cc: Mika Kuoppala Signed-off-by: Guenter Roeck Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=66139 Signed-off-by: Daniel Vetter Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/intel_pm.c | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) --- 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 *de 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;