On Tue, 30 Apr 2019, Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx> wrote: > Currently due to regression CI machine > displays show corrupt picture. > Problem is when CDCLK is as low as 79200, picture gets > unstable, while DSI and DE pll values were > confirmed to be correct. > Limiting to 158400 as agreed with Ville. > > We could not come up with any better solution > yet, as PLL divider values both for MIPI(DSI PLL) and > CDCLK(DE PLL) are correct, however seems that due to some > boundary conditions, when clocking is too low we get > wrong timings for DSI display. > Similar workaround exists for VLV though, so just > took similar condition into use. At least that way > GLK platform will start to be usable again, with > current drm-tip. > > v2: Fixed commit subject as suggested. > > v3: Added generic bugs(crc failures, screen not init > for GLK DSI which might be affected). > > v4: Added references tag for bugs affected. > > Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx> > Acked-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > References: https://bugs.freedesktop.org/show_bug.cgi?id=109267 > References: https://bugs.freedesktop.org/show_bug.cgi?id=103184 Pushed, thanks for the patch. BR, Jani. > --- > drivers/gpu/drm/i915/intel_cdclk.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/drivers/gpu/drm/i915/intel_cdclk.c b/drivers/gpu/drm/i915/intel_cdclk.c > index ae40a8679314..2b23f8500362 100644 > --- a/drivers/gpu/drm/i915/intel_cdclk.c > +++ b/drivers/gpu/drm/i915/intel_cdclk.c > @@ -2277,6 +2277,15 @@ int intel_crtc_compute_min_cdclk(const struct intel_crtc_state *crtc_state) > IS_VALLEYVIEW(dev_priv)) > min_cdclk = max(320000, min_cdclk); > > + /* > + * On Geminilake once the CDCLK gets as low as 79200 > + * picture gets unstable, despite that values are > + * correct for DSI PLL and DE PLL. > + */ > + if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DSI) && > + IS_GEMINILAKE(dev_priv)) > + min_cdclk = max(158400, min_cdclk); > + > if (min_cdclk > dev_priv->max_cdclk_freq) { > DRM_DEBUG_KMS("required cdclk (%d kHz) exceeds max (%d kHz)\n", > min_cdclk, dev_priv->max_cdclk_freq); -- Jani Nikula, Intel Open Source Graphics Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
