From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: [PATCH 23/30] drm/i915: Cache GT fifo count for SandyBridge Date: Tue, 12 Apr 2011 21:31:51 +0100 Message-ID: <1302640318-23165-24-git-send-email-chris@chris-wilson.co.uk> References: <1302640318-23165-1-git-send-email-chris@chris-wilson.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTP id 126349E8BE for ; Tue, 12 Apr 2011 13:32:53 -0700 (PDT) In-Reply-To: <1302640318-23165-1-git-send-email-chris@chris-wilson.co.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org The read back of the available FIFO entries is vital for system stability, but extremely costly. However, we only need a guide so as to avoid eating into the reserved entries and since we are the only consumer we can cache the read of the count from the last write. Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/i915_drv.c | 14 +++++++++----- drivers/gpu/drm/i915/i915_drv.h | 1 + 2 files changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index c416c1d..1146abd 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -287,12 +287,16 @@ void __gen6_gt_force_wake_put(struct drm_i915_private *dev_priv) void __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv) { - int loop = 500; - u32 fifo = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES); - while (fifo < 20 && loop--) { - udelay(10); - fifo = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES); + if (dev_priv->gt_fifo_count < 20 ) { + int loop = 500; + u32 fifo = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES); + while (fifo < 20 && loop--) { + udelay(10); + fifo = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES); + } + dev_priv->gt_fifo_count = fifo; } + dev_priv->gt_fifo_count--; } static int i915_drm_freeze(struct drm_device *dev) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 2f45228..c837e10 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -268,6 +268,7 @@ typedef struct drm_i915_private { int relative_constants_mode; void __iomem *regs; + u32 gt_fifo_count; struct intel_gmbus { struct i2c_adapter adapter; -- 1.7.4.1