drm/i915/dsc: force full modeset whenever DSC is enabled at probe

We lack full state readout of DSC config, which may lead to DSC enable
using a config that's all zeros, failing spectacularly. Force full
modeset and thus compute config at probe to get a sane state, until we
implement DSC state readout. Any fastset that did appear to work with
DSC at probe, worked by coincidence. [1] is an example of a change that
triggered the issue on TGL DSI DSC.

[1] http://patchwork.freedesktop.org/patch/msgid/20200212150102.7600-1-ville.syrjala@linux.intel.com

Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Vandita Kulkarni <vandita.kulkarni@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: stable@vger.kernel.org
Fixes: fbacb15ea8 ("drm/i915/dsc: add basic hardware state readout support")
Acked-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200213140412.32697-3-stanislav.lisovskiy@intel.com
This commit is contained in:
Jani Nikula 2020-02-13 16:04:11 +02:00
parent b18e249bf6
commit a4277aa398

View File

@ -17828,6 +17828,24 @@ static int intel_initial_commit(struct drm_device *dev)
* have readout for pipe gamma enable.
*/
crtc_state->uapi.color_mgmt_changed = true;
/*
* FIXME hack to force full modeset when DSC is being
* used.
*
* As long as we do not have full state readout and
* config comparison of crtc_state->dsc, we have no way
* to ensure reliable fastset. Remove once we have
* readout for DSC.
*/
if (crtc_state->dsc.compression_enable) {
ret = drm_atomic_add_affected_connectors(state,
&crtc->base);
if (ret)
goto out;
crtc_state->uapi.mode_changed = true;
drm_dbg_kms(dev, "Force full modeset for DSC\n");
}
}
}