Re: [PATCH] drm/i915: VGA also requires the power well

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

On Wed, Jun 05, 2013 at 06:05:51PM -0300, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni@intel.com>
> 
> So add a power domain and check for it before we try to read
> VGA_CONTROL.
> 
> This fixes unclaimed register messages that happen on suspend/resume.
> 
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h      | 1 +
>  drivers/gpu/drm/i915/intel_display.c | 3 +++
>  drivers/gpu/drm/i915/intel_pm.c      | 1 +
>  3 files changed, 5 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 46b1f70..d51ce13 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -89,6 +89,7 @@ enum port {
>  #define port_name(p) ((p) + 'A')
>  
>  enum intel_display_power_domain {
> +	POWER_DOMAIN_VGA,
>  	POWER_DOMAIN_PIPE_A,
>  	POWER_DOMAIN_PIPE_B,
>  	POWER_DOMAIN_PIPE_C,
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 4c8fcec..3719d99 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -9950,6 +9950,9 @@ void i915_redisable_vga(struct drm_device *dev)
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	u32 vga_reg = i915_vgacntrl_reg(dev);
>  
> +	if (!intel_display_power_enabled(dev, POWER_DOMAIN_VGA))
> +		return;
> +

So it looks like you're essentially making intel_redisable_vga() a nop
for HSW. Shouldn't we instead enable the power well during resume?

>  	if (I915_READ(vga_reg) != VGA_DISP_DISABLE) {
>  		DRM_DEBUG_KMS("Something enabled VGA plane, disabling it\n");
>  		i915_disable_vga(dev);
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 50fe3d7..47ef4a6 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -5000,6 +5000,7 @@ bool intel_display_power_enabled(struct drm_device *dev,
>  	case POWER_DOMAIN_PIPE_A:
>  	case POWER_DOMAIN_TRANSCODER_EDP:
>  		return true;
> +	case POWER_DOMAIN_VGA:
>  	case POWER_DOMAIN_PIPE_B:
>  	case POWER_DOMAIN_PIPE_C:
>  	case POWER_DOMAIN_PIPE_A_PANEL_FITTER:
> -- 
> 1.8.1.2
> 
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-- 
Ville Syrjälä
Intel OTC