On Thu, 06 Nov 2025, "Kandpal, Suraj" <[email protected]> wrote:
>> Subject: Re: [PATCH 1/7] drm/i915/cx0: Undo the unjustified timeout change
>> 
>> On Wed, 05 Nov 2025, Ville Syrjala <[email protected]> wrote:
>> > From: Ville Syrjälä <[email protected]>
>> >
>> > Undo the bogus timeout change to
>> > intel_cx0_powerdown_change_sequence(). If this was intentional then it
>> > should have been justifie in the commit message.
>> >
>> > This is also now abusing intel_de_wait_custom() in way that prevents
>> > future conversion to poll_timeout_us().
>> >
>> > Fixes: fc9be0a10ca4 ("drm/i915/ltphy: Add a wrapper for LT Phy
>> > powerdown change sequence")
>> > Signed-off-by: Ville Syrjälä <[email protected]>
>> 
>> Reviewed-by: Jani Nikula <[email protected]>
>> 
>> > ---
>> >  drivers/gpu/drm/i915/display/intel_cx0_phy.c | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
>> > b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
>> > index b3b506d0e040..e7fe974129fe 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
>> > +++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
>> > @@ -2830,7 +2830,7 @@ void
>> intel_cx0_powerdown_change_sequence(struct intel_encoder *encoder,
>> >    /* Update Timeout Value */
>> >    if (intel_de_wait_custom(display, buf_ctl2_reg,
>> >
>> intel_cx0_get_powerdown_update(lane_mask), 0,
>> > -
>> XELPDP_PORT_POWERDOWN_UPDATE_TIMEOUT_US, 2, NULL))
>> > +
>> XELPDP_PORT_POWERDOWN_UPDATE_TIMEOUT_US, 0, NULL))
>
> According to Bspec: 74494
> The powerdown change update delay can go from anywhere to 2us to
> 1.2ms

Then use intel_de_wait_for_clear() with a 2 ms timeout. There's no
reason to use intel_de_wait_custom().

BR,
Jani.


-- 
Jani Nikula, Intel

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