[Intel-gfx] [PATCH] drm/i915/vlv: hack to init backlight regs if BIOS fails to do so v2

[Daniel Vetter]

On Wed, Sep 25, 2013 at 02:04:32PM -0700, Jesse Barnes wrote:
> Still digging up the actual VBT info for this, but wanted to get this
> out there for testing, or in case others are also bugged by this.
> 
> This can happen if you boot with an external display connected.  In that
> case, the attached eDP backlight modulation frequency may not be
> programmed, so we need to use something (in this case the value my BIOS
> normally programs with just the internal display enabled).
> 
> v2: fix masking and magic value in read_blc_pwm_ctl (Jani)
> 
> Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=67732
Tested-by: shui yangwei <yangweix.shui at intel.com> (v1)

> ---
>  drivers/gpu/drm/i915/intel_panel.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
> index 8f025c6..5468416 100644
> --- a/drivers/gpu/drm/i915/intel_panel.c
> +++ b/drivers/gpu/drm/i915/intel_panel.c
> @@ -372,6 +372,9 @@ static u32 i915_read_blc_pwm_ctl(struct drm_device *dev)
>  				I915_WRITE(BLC_PWM_CTL2,
>  					   dev_priv->regfile.saveBLC_PWM_CTL2);
>  		}
> +
> +		if (IS_VALLEYVIEW(dev) && !val)
> +			val = 0x0f42ffff;
>  	}
>  
>  	return val;
> @@ -629,10 +632,24 @@ set_level:
>  	spin_unlock_irqrestore(&dev_priv->backlight.lock, flags);
>  }
>  
> +/* FIXME: use VBT vals to init PWM_CTL and PWM_CTL2 correctly */
> +static void intel_panel_init_backlight_regs(struct drm_device *dev)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +
> +	if (IS_VALLEYVIEW(dev)) {
> +		u32 cur_val = I915_READ(BLC_PWM_CTL) &
> +			BACKLIGHT_DUTY_CYCLE_MASK;
> +		I915_WRITE(BLC_PWM_CTL, (0xf42 << 16) | cur_val);
> +	}
> +}
> +
>  static void intel_panel_init_backlight(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  
> +	intel_panel_init_backlight_regs(dev);
> +
>  	dev_priv->backlight.level = intel_panel_get_backlight(dev);
>  	dev_priv->backlight.enabled = dev_priv->backlight.level != 0;
>  }
> -- 
> 1.8.3.1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch