> Subject: Re: [PATCH] drm/i915/ltphy: Return true for TBT scenario during > lt_phy_state compare > > On Tue, Feb 03, 2026 at 08:11:41AM +0530, Suraj Kandpal wrote: > > 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. With that in mind comparing the state > > would be wrong since we really don't touch it. > > Simple return true when we are in tbt mode. > > > > Signed-off-by: Suraj Kandpal <[email protected]> > > --- > > 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; > > It is a relevant state whether the PHY is in TBT mode or in a non-TBT mode, > even if the PHY is programmed by the TBT HW block in TBT mode. So it's not ok > to ignore a difference in this state. Please provide the actual context for > why > the change was added.
Bspec : 74492 We do not write the PLL registers when it comes to TBT Mode that is done by the TBT dock. Since the VDR register are shadow registers our shadow registers will never have those values. Which Means we will always have a state mismatch. This has always been the case since SNPS PHY. Check intel_cx0pll_compare_hw_state int intel_cx0_phy.c too Regards, Suraj Kandpal > > > + > > /* > > * With LT PHY values other than VDR0_CONFIG and VDR2_CONFIG are > > * unreliable. They cannot always be read back since internally > > -- > > 2.34.1 > >
