Re: [PATCH] drm/i915/vlv: Turn off power gate for BIOS-less system.

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

On Thu, Oct 03, 2013 at 11:16:17PM +0800, Chon Ming Lee wrote:
> During system boot up, by default, the power gate for render, media and
> display well still power gated.  Normally, BIOS will turn off the power
> gate.  In the BIOS-less system, the driver need to turn off the power
> gate very early during driver load.
> 
> v2: Move this to intel_uncore_sanitize to allow it to get call during
> resume path. (Daniel)
> v3: Remove redundant write 0 to DPIO_CTL, and use DPIO_RESET instead of
> just 0x1 (Ville)
>     Add turn of power gate for display 2d/render well/media well.
> v4: Remove toggle cmnreset in intel_uncore_sanitize.  Cmnreset should
> toggle after CRI clock source has been selected.  Jesse DPIO reset patch
> which toggle the cmnreset in intel_modeset_init_hw() should handle it.
> (Ville)
> 
> Signed-off-by: Chon Ming Lee <chon.ming.lee@intel.com>

Looks OK as a short term solution.

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

> ---
>  drivers/gpu/drm/i915/i915_reg.h     |    9 +++++++++
>  drivers/gpu/drm/i915/intel_uncore.c |   16 ++++++++++++++++
>  2 files changed, 25 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 3432de4..f14310b 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -361,6 +361,15 @@
>  #define PUNIT_OPCODE_REG_READ			6
>  #define PUNIT_OPCODE_REG_WRITE			7
>  
> +#define PUNIT_REG_PWRGT_CTRL			0x60
> +#define PUNIT_REG_PWRGT_STATUS			0x61
> +#define	  PUNIT_CLK_GATE			1
> +#define	  PUNIT_PWR_RESET			2
> +#define	  PUNIT_PWR_GATE			3
> +#define	  RENDER_PWRGT				(PUNIT_PWR_GATE << 0)
> +#define	  MEDIA_PWRGT				(PUNIT_PWR_GATE << 2)
> +#define	  DISP2D_PWRGT				(PUNIT_PWR_GATE << 6)
> +
>  #define PUNIT_REG_GPU_LFM			0xd3
>  #define PUNIT_REG_GPU_FREQ_REQ			0xd4
>  #define PUNIT_REG_GPU_FREQ_STS			0xd8
> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> index f2753d9..288a3a6 100644
> --- a/drivers/gpu/drm/i915/intel_uncore.c
> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> @@ -301,10 +301,26 @@ static void intel_uncore_forcewake_reset(struct drm_device *dev)
>  
>  void intel_uncore_sanitize(struct drm_device *dev)
>  {
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	u32 reg_val;
> +
>  	intel_uncore_forcewake_reset(dev);
>  
>  	/* BIOS often leaves RC6 enabled, but disable it for hw init */
>  	intel_disable_gt_powersave(dev);
> +
> +	/* Turn off power gate, require especially for the BIOS less system */
> +	if (IS_VALLEYVIEW(dev)) {
> +
> +		mutex_lock(&dev_priv->rps.hw_lock);
> +		reg_val = vlv_punit_read(dev_priv, PUNIT_REG_PWRGT_STATUS);
> +
> +		if (reg_val & (RENDER_PWRGT | MEDIA_PWRGT | DISP2D_PWRGT))
> +			vlv_punit_write(dev_priv, PUNIT_REG_PWRGT_CTRL, 0x0);
> +
> +		mutex_unlock(&dev_priv->rps.hw_lock);
> +
> +	}
>  }
>  
>  /*
> -- 
> 1.7.7.6
> 
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-- 
Ville Syrjälä
Intel OTC