Re: 2.6.32 regression (bisected): Video tearing/glitching with T400 laptops

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Mon, 12 Oct 2009 20:46:51 +0200
"Carlos R. Mafra" <crmafra2@gmail.com> wrote:

> On Mon 12.Oct'09 at  9:54:38 -0700, Jesse Barnes wrote:
> > > 
> > > Nope, unfortunately, it's not helping on my T400 laptop.  I'm
> > > still getting huge amounts of glitching and tearing with this
> > > patch applied against -rc3.
> > > 
> > > What I'm using for now to fix up my system is this patch.
> > > 
> > 
> > How about this one?  I have one more idea to try out if this doesn't
> > work (hacking on it now).
> 
> I was also experiencing something very similar to Theodore's bug 
> report and, at least for me, the patch below fixed the issue (the
> previous one also had no effect).

Cool, good to hear.  Hopefully Ted and Keith will confirm too.

-- 
Jesse Barnes, Intel Open Source Technology Center

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 7a5fb79..1451945 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1047,7 +1047,7 @@ static void g4x_enable_fbc(struct drm_crtc *crtc, unsigned long interval)
 	dev_priv->cfb_fence = obj_priv->fence_reg;
 	dev_priv->cfb_plane = intel_crtc->plane;
 
-	dpfc_ctl = plane | DPFC_SR_EN | DPFC_CTL_LIMIT_1X;
+	dpfc_ctl = plane | DPFC_CTL_LIMIT_1X;
 	if (obj_priv->tiling_mode != I915_TILING_NONE) {
 		dpfc_ctl |= DPFC_CTL_FENCE_EN | dev_priv->cfb_fence;
 		I915_WRITE(DPFC_CHICKEN, DPFC_HT_MODIFY);