On Tue, 01 Nov 2016, "Pandiyan, Dhinakaran" <dhinakaran.pandiyan@xxxxxxxxx> wrote: > On Tue, 2016-11-01 at 21:35 +0200, Jani Nikula wrote: >> On Tue, 01 Nov 2016, Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx> wrote: >> > According to BSpec, cdclk for BDW has to be not less than 432 MHz with DP >> > audio enabled, port width x4, and link rate HBR2 (5.4 GHz). With cdclk less >> > than 432 MHz, enabling audio leads to pipe FIFO underruns and displays >> > cycling on/off. >> > >> > Let's apply this work around to GEN9 platforms too, as it fixes the same >> > issue. >> >> I'm too tired to read bspec now, but is gen9 really the answer, or just >> Skylake? >> >> > > Gen9, applies to BXT and KBL as well. I'll take your word for it, and with that, Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx> > > -DK > >> > >> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97907 >> > Cc: stable@xxxxxxxxxxxxxxx >> > Cc: Libin Yang <libin.yang@xxxxxxxxxxxxxxx> >> > Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx> >> > --- >> > drivers/gpu/drm/i915/intel_display.c | 6 ++++-- >> > 1 file changed, 4 insertions(+), 2 deletions(-) >> > >> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c >> > index 37483ee..c0ae147 100644 >> > --- a/drivers/gpu/drm/i915/intel_display.c >> > +++ b/drivers/gpu/drm/i915/intel_display.c >> > @@ -10264,8 +10264,10 @@ static void bxt_modeset_commit_cdclk(struct drm_atomic_state *old_state) >> > static int bdw_adjust_min_pipe_pixel_rate(struct intel_crtc_state *crtc_state, >> > int pixel_rate) >> > { >> > + struct drm_device *dev = crtc_state->base.crtc->dev; >> >> Nitpick, I guess I'd make that >> >> struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev); >> >> but no big deal. >> >> > + >> > /* pixel rate mustn't exceed 95% of cdclk with IPS on BDW */ >> > - if (crtc_state->ips_enabled) >> > + if (IS_BROADWELL(to_i915(dev)) && crtc_state->ips_enabled) >> > pixel_rate = DIV_ROUND_UP(pixel_rate * 100, 95); >> > >> > /* BSpec says "Do not use DisplayPort with CDCLK less than >> > @@ -10307,7 +10309,7 @@ static int ilk_max_pixel_rate(struct drm_atomic_state *state) >> > >> > pixel_rate = ilk_pipe_pixel_rate(crtc_state); >> > >> > - if (IS_BROADWELL(dev_priv)) >> > + if (IS_BROADWELL(dev_priv) || IS_GEN9(dev_priv)) >> > pixel_rate = bdw_adjust_min_pipe_pixel_rate(crtc_state, >> > pixel_rate); >> > -- Jani Nikula, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html