From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesse Barnes Subject: Re: [PATCH] drm/i915: fix errata for sync flush enable on 845G/830M Date: Mon, 9 Aug 2010 09:45:38 -0700 Message-ID: <20100809094538.612f9f8a@virtuousgeek.org> References: <1281292780-28200-1-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 cpoproxy2-pub.bluehost.com (cpoproxy2-pub.bluehost.com [67.222.39.38]) by gabe.freedesktop.org (Postfix) with SMTP id E93F09E777 for ; Mon, 9 Aug 2010 09:45:41 -0700 (PDT) In-Reply-To: <1281292780-28200-1-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: Chris Wilson Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Sun, 8 Aug 2010 19:39:40 +0100 Chris Wilson wrote: > From: Zhenyu Wang > > The sync flush enable mask on 845G and 830M is flipped. > So driver should invert it usage. > > Signed-off-by: Zhenyu Wang > Reviewed-by: Chris Wilson > --- > drivers/gpu/drm/i915/i915_dma.c | 10 ++++++++-- > 1 files changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c > index f19ffe8..4b6c2f8 100644 > --- a/drivers/gpu/drm/i915/i915_dma.c > +++ b/drivers/gpu/drm/i915/i915_dma.c > @@ -1356,6 +1356,7 @@ static int i915_load_modeset_init(struct drm_device *dev, > { > struct drm_i915_private *dev_priv = dev->dev_private; > int fb_bar = IS_I9XX(dev) ? 2 : 0; > + u32 instpm_val; > int ret = 0; > > dev->mode_config.fb_base = pci_resource_start(dev->pdev, fb_bar) & > @@ -1432,9 +1433,14 @@ static int i915_load_modeset_init(struct drm_device *dev, > > /* > * Initialize the hardware status page IRQ location. > + * errata: on 845G and 830M, bit 21's polarity is reversed, > + * so the usage is inverted. > */ > - > - I915_WRITE(INSTPM, (1 << 5) | (1 << 21)); > + if (IS_845G(dev) || IS_I830(dev)) > + instpm_val = (1 << 5) | (0 << 21); > + else > + instpm_val = (1 << 5) | (1 << 21); > + I915_WRITE(INSTPM, instpm_val); > > ret = intel_fbdev_init(dev); > if (ret) Is this hack even needed? I noticed on my 945GM that INSTDONE has a stuck bit when I use this code, removing it didn't seem to have any negative effects... If it really is necessary we should probably document it better and ideally move it to somewhere better like where we program the clock gating workarounds. -- Jesse Barnes, Intel Open Source Technology Center