Re: [PATCH 06/10] drm/i915/psr: set CHICKEN_TRANS for psr2

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: vathsala nagaraju <vathsala.nagaraju@intel.com>
Cc: intel-gfx@lists.freedesktop.org,
	Patil Deepti <deepti.patil@intel.com>,
	dri-devel@lists.freedesktop.org,
	Rodrigo Vivi <rodrigo.vivi@intel.com>
Subject: Re: [PATCH 06/10] drm/i915/psr: set CHICKEN_TRANS for psr2
Date: Tue, 10 Jan 2017 13:08:20 +0200	[thread overview]
Message-ID: <20170110110820.GX31595@intel.com> (raw)
In-Reply-To: <1483967295-15224-1-git-send-email-vathsala.nagaraju@intel.com>

On Mon, Jan 09, 2017 at 06:38:15PM +0530, vathsala nagaraju wrote:
> As per bpsec, CHICKEN_TRANS_EDP bit 12 ,15 must be programmed in
> psr2 enable sequence.
> Program Transcoder EDP VSC DIP header with a valid setting for PSR2
> and Set CHICKEN_TRANS_EDP(0x420cc) bit 12 for programmable header
> packet.
> Set CHICKEN_TRANS_EDP(0x420cc) bit 15 if Y coordinate is supported
> 
> v2: (Rodrigo)
> - move CHICKEN_TRANS_EDP bit set logic right after setup_vsc
> 
> v3:(Rodrigo)
> - initialize chicken_trans to CHICKEN_TRANS_BIT12 instead of 0
> 
> v4:(chris wilson)
> - use BIT(12), remove CHICKEN_TRANS_BIT12
> - remove unnecessary comments
> - update commit message
> 
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Jim Bride <jim.bride@linux.intel.com>
> Signed-off-by: vathsala nagaraju <vathsala.nagaraju@intel.com>
> Signed-off-by: Patil Deepti <deepti.patil@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_reg.h  | 5 +++++
>  drivers/gpu/drm/i915/intel_psr.c | 5 +++++
>  2 files changed, 10 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 7830e6e..3299e01 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6449,6 +6449,11 @@ enum {
>  #define  BDW_DPRS_MASK_VBLANK_SRD	(1 << 0)
>  #define CHICKEN_PIPESL_1(pipe) _MMIO_PIPE(pipe, _CHICKEN_PIPESL_1_A, _CHICKEN_PIPESL_1_B)
>  
> +#define CHICKEN_TRANS_A         0x420c0
> +#define CHICKEN_TRANS_B         0x420c4
> +#define CHICKEN_TRANS(trans) _MMIO_TRANS(trans, CHICKEN_TRANS_A, CHICKEN_TRANS_B)
> +#define TRANS_EDP              3
> +
>  #define DISP_ARB_CTL	_MMIO(0x45000)
>  #define  DISP_FBC_MEMORY_WAKE		(1<<31)
>  #define  DISP_TILE_SURFACE_SWIZZLING	(1<<13)
> diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
> index b28891b..b1686c2 100644
> --- a/drivers/gpu/drm/i915/intel_psr.c
> +++ b/drivers/gpu/drm/i915/intel_psr.c
> @@ -475,6 +475,7 @@ void intel_psr_enable(struct intel_dp *intel_dp)
>  	struct drm_device *dev = intel_dig_port->base.base.dev;
>  	struct drm_i915_private *dev_priv = to_i915(dev);
>  	struct intel_crtc *crtc = to_intel_crtc(intel_dig_port->base.base.crtc);
> +	u32 chicken = 0;
>  
>  	if (!HAS_PSR(dev_priv)) {
>  		DRM_DEBUG_KMS("PSR not supported on this platform\n");
> @@ -505,6 +506,10 @@ void intel_psr_enable(struct intel_dp *intel_dp)
>  				dev_priv->psr.psr2_support = false;
>  			else
>  				skl_psr_setup_su_vsc(intel_dp);
> +			chicken = BIT(12);
> +			if (dev_priv->psr.y_cord_support)
> +				chicken |= BIT(15);

In cases like this I think the better option is to invent a decent
name for the bit. Otherwise no one can figure out what the code does
without consulting the spec.

> +			I915_WRITE(CHICKEN_TRANS(TRANS_EDP), chicken);
>  		} else {
>  			/* set up vsc header for psr1 */
>  			hsw_psr_setup_vsc(intel_dp);
> -- 
> 1.9.1
> 
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> dri-devel@lists.freedesktop.org
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-- 
Ville Syrjälä
Intel OTC
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