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). Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx> Acked-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Generic bugs affected: https://bugs.freedesktop.org/show_bug.cgi?id=109267 https://bugs.freedesktop.org/show_bug.cgi?id=103184 --- 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); -- 2.17.1 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
