[PATCH v2] drm/i915/ltphy: Return true for TBT scenario during lt_phy_state compare

[Suraj Kandpal <suraj.kandpal@intel.com>]

TBT PHY is enablement/disablement is handled by its own TBT module.
We do not play a big part in it's state management, that being take care
by it's own TBT modeule.
The PHY/PLL TypeC mode (TBT, DP-alt) can change after the PLL state was
computed for a modeset, so the state verification after the modeset
sequence would indicate a mismatch in case the mode changed from DP-alt
to TBT, or from TBT to DP-alt mode. To avoid such a mismatch error the
verification is skipped if the mode for either the read-out or the
computed state is TBT (where that TBT PLL state doesn't reflect anyway
the PLL's actual HW state).
Simply return true when we are in tbt mode.

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
---
V1 -> V2:
- Reframe commit messgae with give the full explanation as to why we
skip verification (Imre)

 drivers/gpu/drm/i915/display/intel_lt_phy.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_lt_phy.c b/drivers/gpu/drm/i915/display/intel_lt_phy.c
index 04f63bdd0b87..27ad8407606b 100644
--- a/drivers/gpu/drm/i915/display/intel_lt_phy.c
+++ b/drivers/gpu/drm/i915/display/intel_lt_phy.c
@@ -2158,6 +2158,9 @@ bool
 intel_lt_phy_pll_compare_hw_state(const struct intel_lt_phy_pll_state *a,
 				  const struct intel_lt_phy_pll_state *b)
 {
+	if (a->tbt_mode || b->tbt_mode)
+		return true;
+
 	/*
 	 * With LT PHY values other than VDR0_CONFIG and VDR2_CONFIG are
 	 * unreliable. They cannot always be read back since internally
-- 
2.34.1