Re: [PATCH 2/2] drm/i915: Clear PCODE_DATA1 on SNB+

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Fri, Sep 05, 2014 at 01:53:12PM +0100, Damien Lespiau wrote:
> Ville found out that the DATA1 register exists since SNB with some
> scarce apparitions in the specs throughout the times. In his own words:
> 
>   Also according to Bspec the mailbox data1 register already existed
>   since snb.  The hsw cdclk change sequence also mentions that it should
>   be set to 0, but eg. the bdw IPS sequence doesn't mention it. I guess
>   in theory some pcode command might cause it to be clobbered, so I'm
>   thinking we should just explicitly set it to 0 for all platforms in
>   the pcode read/write functions
> 
> Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> ---
>  drivers/gpu/drm/i915/i915_reg.h | 2 +-
>  drivers/gpu/drm/i915/intel_pm.c | 3 +--
>  2 files changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 5a7adb1..56cccde 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -5952,8 +5952,8 @@ enum skl_disp_power_wells {
>  #define GEN6_PCODE_DATA				0x138128
>  #define   GEN6_PCODE_FREQ_IA_RATIO_SHIFT	8
>  #define   GEN6_PCODE_FREQ_RING_RATIO_SHIFT	16
> +#define GEN6_PCODE_DATA1			0x13812C
>  
> -#define GEN9_PCODE_DATA1			0x13812C
>  #define   GEN9_PCODE_READ_MEM_LATENCY		0x6
>  #define   GEN9_MEM_LATENCY_LEVEL_MASK		0xFF
>  #define   GEN9_MEM_LATENCY_LEVEL_1_5_SHIFT	8
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 3f69f9a..7bc8f73 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -8716,8 +8716,7 @@ int sandybridge_pcode_read(struct drm_i915_private *dev_priv, u8 mbox, u32 *val)
>  	}
>  
>  	I915_WRITE(GEN6_PCODE_DATA, *val);
> -	if (INTEL_INFO(dev_priv)->gen >= 9)
> -		I915_WRITE(GEN9_PCODE_DATA1, 0);
> +	I915_WRITE(GEN6_PCODE_DATA1, 0);
>  	I915_WRITE(GEN6_PCODE_MAILBOX, GEN6_PCODE_READY | mbox);
>  
>  	if (wait_for((I915_READ(GEN6_PCODE_MAILBOX) & GEN6_PCODE_READY) == 0,
> -- 
> 1.8.3.1

-- 
Ville Syrjälä
Intel OTC