From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: [PATCH] drm/i915: implement WaIssueDummyWriteToWakeupFromRC6 Date: Thu, 18 Oct 2012 14:14:14 +0200 Message-ID: <1350562454-5809-1-git-send-email-daniel.vetter@ffwll.ch> References: <275ffc$71to91@fmsmga002.fm.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wg0-f43.google.com (mail-wg0-f43.google.com [74.125.82.43]) by gabe.freedesktop.org (Postfix) with ESMTP id 9DB359E815 for ; Thu, 18 Oct 2012 04:56:23 -0700 (PDT) Received: by mail-wg0-f43.google.com with SMTP id dq11so5764108wgb.12 for ; Thu, 18 Oct 2012 04:56:22 -0700 (PDT) In-Reply-To: <275ffc$71to91@fmsmga002.fm.intel.com> 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 Graphics Development Cc: Daniel Vetter List-Id: intel-gfx@lists.freedesktop.org Or at least our best understanding of it. Reviewed-by: Chris Wilson Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_drv.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index a7837e5..c3f4f04 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -1131,9 +1131,20 @@ static bool IS_DISPLAYREG(u32 reg) return true; } +static void +ilk_dummy_write(struct drm_i915_private *dev_priv) +{ + /* Ilk w/a: Issue a dummy write to wake up the chip from rc6 before + * touching it for real. MI_MODE is masked, hence harmless to write 0 + * into. */ + I915_WRITE_NOTRACE(MI_MODE, 0); +} + #define __i915_read(x, y) \ u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg) { \ u##x val = 0; \ + if (IS_GEN5(dev_priv->dev)) \ + ilk_dummy_write(dev_priv); \ if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \ unsigned long irqflags; \ spin_lock_irqsave(&dev_priv->gt_lock, irqflags); \ @@ -1165,6 +1176,8 @@ void i915_write##x(struct drm_i915_private *dev_priv, u32 reg, u##x val) { \ if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \ __fifo_ret = __gen6_gt_wait_for_fifo(dev_priv); \ } \ + if (IS_GEN5(dev_priv->dev)) \ + ilk_dummy_write(dev_priv); \ if (IS_VALLEYVIEW(dev_priv->dev) && IS_DISPLAYREG(reg)) { \ write##y(val, dev_priv->regs + reg + 0x180000); \ } else { \ -- 1.7.10.4