drm/i915/display: Skip TRANS_VTOTAL.Vtotal write on NVL pre-C0

On Nova Lake A/B steppings the GOP breaks DP-Alt / native DP output
when TRANS_VTOTAL.Vtotal is programmed with a non-zero value, and the
initial hardware readout of that field on such systems ends up in
adjusted_mode.crtc_vtotal = 1 -- tripping the DSB scanline WARN in
assert_dsl_ok() during intel_initial_commit.

Keep TRANS_VTOTAL.Vtotal at 0 on Nova Lake pre-C0 (A0..B3) in both
transcoder timing paths, and restore adjusted_mode.crtc_vtotal from
TRANS_VRR_VMIN in intel_vrr_get_config() so downstream state stays
consistent.

Fixes: f26a8df8dff9 ("drm/i915/display: Program TRANS_VTOTAL from mode vtotal")
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patch.msgid.link/20260703032653.2122784-1-suraj.kandpal@intel.com

0 files changed, 0 insertions, 0 deletions