On Wed, Sep 26, 2012 at 06:27:51PM +0300, Jani Nikula wrote: > The dithering introduced in > > commit 3b5c78a35cf7511c15e09a9b0ffab290a42d9bcf > Author: Adam Jackson <ajax at redhat.com> > Date: Tue Dec 13 15:41:00 2011 -0800 > > drm/i915/dp: Dither down to 6bpc if it makes the mode fit > > stores the INTEL_MODE_DP_FORCE_6BPC flag in the private_flags of the > adjusted mode, while intel_choose_pipe_bpp_dither() determining the color > depth was passed the original mode, without the flag, so it would never > have any effect. However, the BPC was clamped by VBT settings, making > things work by coincidence, until that part was removed in > > commit 4344b813f105a19f793f1fd93ad775b784648b95 > Author: Daniel Vetter <daniel.vetter at ffwll.ch> > Date: Fri Aug 10 11:10:20 2012 +0200 > > Pass adjusted_mode instead of mode to intel_choose_pipe_bpp_dither() to > make INTEL_MODE_DP_FORCE_6BPC have effect. > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=47621 > CC: stable at vger.kernel.org > Signed-off-by: Jani Nikula <jani.nikula at intel.com> Awesome piece of debugging here. But can I point you to i9xx_crtc_mode_set, where the same bug exists an ask for v2? Cheers, Daniel > --- > drivers/gpu/drm/i915/intel_display.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c > index 08c3f69..0a9802a 100644 > --- a/drivers/gpu/drm/i915/intel_display.c > +++ b/drivers/gpu/drm/i915/intel_display.c > @@ -4936,7 +4936,8 @@ static int ironlake_crtc_mode_set(struct drm_crtc *crtc, > intel_crtc_update_cursor(crtc, true); > > /* determine panel color depth */ > - dither = intel_choose_pipe_bpp_dither(crtc, fb, &intel_crtc->bpp, mode); > + dither = intel_choose_pipe_bpp_dither(crtc, fb, &intel_crtc->bpp, > + adjusted_mode); > if (is_lvds && dev_priv->lvds_dither) > dither = true; > > -- > 1.7.9.5 > -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
