On Tue, May 28, 2013 at 10:39:07AM -0700, Stuart Abercrombie wrote: > Any comments? > > Without this, plugging one of the older Chromebook models into a Dell U3011 > monitor produces a garbled display at the default 2048x1280 resolution. > > The original threshold was apparently fairly arbitrary: > > http://cgit.freedesktop.org/~anholt/xf86-video-intel/commit/?id=8fcf9a81179ee8577ddab5e904c58fbfd14cf59c Do you see any pipe underruns without this patch? There are some not-yet implemented tricks we should be pulling around re-splitting DSP_ARB fifo entries, which tend to totally kill high-res modes. -Daniel > . > > Stuart > > > On Mon, May 20, 2013 at 11:15 AM, Stuart Abercrombie < > sabercrombie at chromium.org> wrote: > > > 90% of core speed (=180MHz dot clock) is too high for 2048x1280 to get > > pixel doubling on Pineview, which it needs to avoid underruns, so > > lower this to 85%. > > > > Signed-off-by: Stuart Abercrombie <sabercrombie at chromium.org> > > --- > > drivers/gpu/drm/i915/intel_display.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/intel_display.c > > b/drivers/gpu/drm/i915/intel_display.c > > index efe8299..9c924e9 100644 > > --- a/drivers/gpu/drm/i915/intel_display.c > > +++ b/drivers/gpu/drm/i915/intel_display.c > > @@ -4564,14 +4564,14 @@ static void i9xx_set_pipeconf(struct intel_crtc > > *intel_crtc) > > pipeconf = I915_READ(PIPECONF(intel_crtc->pipe)); > > > > if (intel_crtc->pipe == 0 && INTEL_INFO(dev)->gen < 4) { > > - /* Enable pixel doubling when the dot clock is > 90% of > > the (display) > > + /* Enable pixel doubling when the dot clock is > 85% of > > the (display) > > * core speed. > > * > > * XXX: No double-wide on 915GM pipe B. Is that the only > > reason for the > > * pipe == 0 check? > > */ > > if (intel_crtc->config.requested_mode.clock > > > - dev_priv->display.get_display_clock_speed(dev) * 9 / > > 10) > > + dev_priv->display.get_display_clock_speed(dev) * 17 / > > 20) > > pipeconf |= PIPECONF_DOUBLE_WIDE; > > else > > pipeconf &= ~PIPECONF_DOUBLE_WIDE; > > -- > > 1.8.2.1 > > > > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx at lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
