[PATCH 3/3] drm/i915/dsb: Always set DSB_SKIP_WAITS_EN

[Manna, Animesh]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Ville
> Syrjala
> Sent: Wednesday, March 6, 2024 9:38 AM
> To: intel-gfx at lists.freedesktop.org
> Subject: [PATCH 3/3] drm/i915/dsb: Always set DSB_SKIP_WAITS_EN
> 
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Bspec asks us to always set the DSB_SKIP_WAITS_EN bit in DSB_CHICKEN.
> This seems to instruct DSB to skip vblank and scanline waits when PSR is
> entered.
> 
> I don't think we have any cases currently where we would want to enter PSR
> while DSB is waiting for something, but let's set the bit anyway to align with
> Bspec's wishes.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Reviewed-by: Animesh Manna <animesh.manna at intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_dsb.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c
> b/drivers/gpu/drm/i915/display/intel_dsb.c
> index e4515bf92038..4baaa92ceaec 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsb.c
> +++ b/drivers/gpu/drm/i915/display/intel_dsb.c
> @@ -343,12 +343,13 @@ static int intel_dsb_dewake_scanline(const struct
> intel_crtc_state *crtc_state)  static u32 dsb_chicken(struct intel_crtc *crtc)  {
>  	if (crtc->mode_flags & I915_MODE_FLAG_VRR)
> -		return DSB_CTRL_WAIT_SAFE_WINDOW |
> +		return DSB_SKIP_WAITS_EN |
> +			DSB_CTRL_WAIT_SAFE_WINDOW |
>  			DSB_CTRL_NO_WAIT_VBLANK |
>  			DSB_INST_WAIT_SAFE_WINDOW |
>  			DSB_INST_NO_WAIT_VBLANK;
>  	else
> -		return 0;
> +		return DSB_SKIP_WAITS_EN;
>  }
> 
>  static void _intel_dsb_commit(struct intel_dsb *dsb, u32 ctrl,
> --
> 2.43.0