drm/i915/dp: Fix DSC state computation

When computing the encoder/CRTC state multiple times, such as during
iteration over the possible pipe joiner configurations, it must be
ensured that all state is explicitly initialized each time. At the
moment, this is not guaranteed for the DSC/FEC state within the
encoder/CRTC state. In one iteration trying a pipe joiner configuration,
the DSC state may get initialized without computing the full
CRTC/encoder state due to the given joiner configuration being
impossible. When the same CRTC/encoder state is recomputed in a
subsequent iteration, the previously set non-zero - now stale - DSC/FEC
state may still be present, which is unexpected if a non-DSC
configuration is being computed.

This can lead to a DSC state mismatch error if multiple joiner
configurations are evaluated and the working configuration ultimately
turns out to be a non-DSC one.

Follow the existing pattern and compute the full (DSC/FEC) state on all
code paths (including now the non-DSC path as well) to fix the issue.

Fixes: 1f1e3e5c65f6 ("drm/i915/dp: Rework pipe joiner logic in compute_config")
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/7512
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260302102838.1522499-1-imre.deak@intel.com

0 files changed, 0 insertions, 0 deletions