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

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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: f26a8df8df ("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

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This commit is contained in:

Suraj Kandpal 2026-07-03 08:56:54 +05:30

parent cd0121502c

commit a78d11e785

2 changed files with 15 additions and 0 deletions

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9

drivers/gpu/drm/i915/display/intel_display.c

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6

drivers/gpu/drm/i915/display/intel_vrr.c

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