[Intel-gfx] [PATCH] drm/i915/mtl: Use int for entry setup frames

[Kahola, Mika]

> -----Original Message-----
> From: Hajda, Andrzej <andrzej.hajda at intel.com>
> Sent: Tuesday, November 14, 2023 12:22 PM
> To: Kahola, Mika <mika.kahola at intel.com>; intel-gfx at lists.freedesktop.org
> Subject: Re: [Intel-gfx] [PATCH] drm/i915/mtl: Use int for entry setup frames
> 
> On 13.11.2023 10:37, Mika Kahola wrote:
> > At least one TGL had regression when using u8 types for entry setup
> > frames calculation. So, let's switch to use ints instead.
> 
> This explanation is missing the most important part - why int?
> 
> I guess it is because intel_psr_entry_setup_frames can return -ETIME, which converted to u8 and then int becomes not what we
> would expect.
> And fixes tag is missing.

I will add the fixes and improve the explanation.

Thanks for the comments and reviews.

-Mika-
> 
> Regards
> Andrzej
> 
> >
> > Signed-off-by: Mika Kahola <mika.kahola at intel.com>
> > ---
> >   drivers/gpu/drm/i915/display/intel_psr.c | 6 +++---
> >   1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_psr.c
> > b/drivers/gpu/drm/i915/display/intel_psr.c
> > index 3691f882e1c0..a4417e85f92a 100644
> > --- a/drivers/gpu/drm/i915/display/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> > @@ -1093,12 +1093,12 @@ static bool _compute_psr2_wake_times(struct intel_dp *intel_dp,
> >   	return true;
> >   }
> >
> > -static u8 intel_psr_entry_setup_frames(struct intel_dp *intel_dp,
> > -				       const struct drm_display_mode *adjusted_mode)
> > +static int intel_psr_entry_setup_frames(struct intel_dp *intel_dp,
> > +					const struct drm_display_mode *adjusted_mode)
> >   {
> >   	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> >   	int psr_setup_time = drm_dp_psr_setup_time(intel_dp->psr_dpcd);
> > -	u8 entry_setup_frames = 0;
> > +	int entry_setup_frames = 0;
> >
> >   	if (psr_setup_time < 0) {
> >   		drm_dbg_kms(&i915->drm,