[PATCH 6/9] drm/i915: Move the min/max scanline sanity check into intel_vblank_evade()

[Shankar, Uma]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Ville
> Syrjala
> Sent: Wednesday, December 13, 2023 3:55 PM
> To: intel-gfx at lists.freedesktop.org
> Subject: [PATCH 6/9] drm/i915: Move the min/max scanline sanity check into
> intel_vblank_evade()
> 
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> There isn't really any reason to make the caller suffer through checking the vblank
> evasion min/max scanlines. If we somehow ended up with bogus values (which
> really shouldn't happen) then just skip the actual vblank evasion loop but
> otherwise plow ahead as normal.
> 
> The only "real" change is that we now get+put a vblank reference even if the
> min/max values are bogus, previously we skipped directly to the end.

Looks fine to me.
Reviewed-by: Uma Shankar <uma.shankar at intel.com>

> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_crtc.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_crtc.c
> b/drivers/gpu/drm/i915/display/intel_crtc.c
> index 26a07b2219bf..11a6a4b0a258 100644
> --- a/drivers/gpu/drm/i915/display/intel_crtc.c
> +++ b/drivers/gpu/drm/i915/display/intel_crtc.c
> @@ -544,6 +544,9 @@ static int intel_vblank_evade(struct
> intel_vblank_evade_ctx *evade)
>  	DEFINE_WAIT(wait);
>  	int scanline;
> 
> +	if (evade->min <= 0 || evade->max <= 0)
> +		return 0;
> +
>  	for (;;) {
>  		/*
>  		 * prepare_to_wait() has a memory barrier, which guarantees
> @@ -633,8 +636,6 @@ void intel_pipe_update_start(struct intel_atomic_state
> *state,
>  		intel_crtc_vblank_work_init(new_crtc_state);
> 
>  	intel_vblank_evade_init(old_crtc_state, new_crtc_state, &evade);
> -	if (evade.min <= 0 || evade.max <= 0)
> -		goto irq_disable;
> 
>  	if (drm_WARN_ON(&dev_priv->drm, drm_crtc_vblank_get(&crtc-
> >base)))
>  		goto irq_disable;
> --
> 2.41.0