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

[Imre Deak <imre.deak@intel.com>]

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 <suraj.kandpal@intel.com>
> ---
>  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.

> +
>  	/*
>  	 * With LT PHY values other than VDR0_CONFIG and VDR2_CONFIG are
>  	 * unreliable. They cannot always be read back since internally
> -- 
> 2.34.1
>