On Wed, Sep 02, 2020 at 03:12:01PM +0300, Lisovskiy, Stanislav wrote: > On Wed, Sep 02, 2020 at 01:31:09PM +0300, Ville Syrjälä wrote: > > On Tue, Sep 01, 2020 at 06:10:36PM +0300, Kai Vehmanen wrote: > > > In commit 4f0b4352bd26 ("drm/i915: Extract cdclk requirements checking > > > to separate function") the order of force_min_cdclk_changed check and > > > intel_modeset_checks(), was reversed. This broke the mechanism to > > > immediately force a new CDCLK minimum, and lead to driver probe > > > errors for display audio on GLK platform with 5.9-rc1 kernel. Fix > > > the issue by moving intel_modeset_checks() call later. > > > > Yep. I eyeed this same code recently and noticed the same bug. > > The one thing I didn't yet figure out is whether there is some > > subtle ordering requirement that was the reason for the change. > > But considering intel_modeset_checks() doesn't really do much > > anymore I think it should be safe. > > > > Sadly CI has been lumping all underrun errors under some ancient > > bugs, so no one noticed that things started to fail when this > > regression was introduced :( > > > > Reviewed-by: Ville Syrjälä <ville.syrj...@linux.intel.com> > > What surprises me here, is that the actual patch has been sent > and merged during late spring I think and we figure out that there was > a regression only by now. > For example I figured out this only today. When I was doing that change, > was actually aware that the change is actually quite significant as > it changes the way how we deal with CDCLK, however those were necessary > as we had a massive FIFO underrun issues at the moment. However CI didn't > show any problems, so we went ahead with this.
I spotted some CI logs that show underruns due to this regression, but the results just got lumped in with other older underrun bugs, and thus CI results were always "success" :/ I think we need to kill off all underrun related CI filters and start from scratch. Otherwise new bugs will keep slipping through. > > > > > > > > > Fixes: 4f0b4352bd26 ("drm/i915: Extract cdclk requirements checking to > > > separate function)" > > > BugLink: https://github.com/thesofproject/linux/issues/2410 > > > Signed-off-by: Kai Vehmanen <kai.vehma...@linux.intel.com> > > > --- > > > drivers/gpu/drm/i915/display/intel_display.c | 10 ++++------ > > > 1 file changed, 4 insertions(+), 6 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/i915/display/intel_display.c > > > b/drivers/gpu/drm/i915/display/intel_display.c > > > index 7d50b7177d40..8caeed23037c 100644 > > > --- a/drivers/gpu/drm/i915/display/intel_display.c > > > +++ b/drivers/gpu/drm/i915/display/intel_display.c > > > @@ -15009,12 +15009,6 @@ static int intel_atomic_check(struct drm_device > > > *dev, > > > if (dev_priv->wm.distrust_bios_wm) > > > any_ms = true; > > > > > > - if (any_ms) { > > > - ret = intel_modeset_checks(state); > > > - if (ret) > > > - goto fail; > > > - } > > > - > > > intel_fbc_choose_crtc(dev_priv, state); > > > ret = calc_watermark_data(state); > > > if (ret) > > > @@ -15029,6 +15023,10 @@ static int intel_atomic_check(struct drm_device > > > *dev, > > > goto fail; > > > > > > if (any_ms) { > > > + ret = intel_modeset_checks(state); > > > + if (ret) > > > + goto fail; > > > + > > > ret = intel_modeset_calc_cdclk(state); > > > if (ret) > > > return ret; > > > -- > > > 2.27.0 > > > > -- > > Ville Syrjälä > > Intel -- Ville Syrjälä Intel _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx