[Intel-gfx] [PATCH] drm/i915: Fix VGA_DISP_DISABLE check

[Jesse Barnes]

On Fri,  4 Oct 2013 20:32:25 +0300
ville.syrjala at linux.intel.com wrote:

> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> The VGACNTRL register contains a bunch of other stuff besides
> the VGA_DISP_DISABLE bit. When we write the register we always set those
> other bits to zero, so normally the current check would work.
> 
> However on HSW disabling and re-enabling the power well will reset the
> VGACNTRL register to its default value, which has several of the other
> bits set as well.
> 
> So only look at the VGA_DISP_DISABLE bit when checking whether the VGA
> plane needs re-disabling.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 0ba0af4..925a387 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -10659,7 +10659,7 @@ void i915_redisable_vga(struct drm_device *dev)
>  	    (I915_READ(HSW_PWR_WELL_DRIVER) & HSW_PWR_WELL_STATE_ENABLED) == 0)
>  		return;
>  
> -	if (I915_READ(vga_reg) != VGA_DISP_DISABLE) {
> +	if (!(I915_READ(vga_reg) & VGA_DISP_DISABLE)) {
>  		DRM_DEBUG_KMS("Something enabled VGA plane, disabling it\n");
>  		i915_disable_vga(dev);
>  		i915_disable_vga_mem(dev);

Looks good.

Reviewed-by: Jesse Barnes <jbarnes at virtuousgeek.org>

-- 
Jesse Barnes, Intel Open Source Technology Center