Re: [PATCH 04/15] drm/i915: don't touch the PF regs if the power well is down

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, Mar 06, 2013 at 08:03:11PM -0300, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni@intel.com>
> 
> This solves some "unclaimed register" messages when booting the
> machine with eDP attached.
> 
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c |    6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index bd27336..9a9f6d7 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -3584,8 +3584,10 @@ static void haswell_crtc_disable(struct drm_crtc *crtc)
>  	intel_ddi_disable_transcoder_func(dev_priv, cpu_transcoder);
>  
>  	/* Disable PF */
> -	I915_WRITE(PF_CTL(pipe), 0);
> -	I915_WRITE(PF_WIN_SZ(pipe), 0);
> +	if (!intel_power_well_is_down(dev)) {
> +		I915_WRITE(PF_CTL(pipe), 0);
> +		I915_WRITE(PF_WIN_SZ(pipe), 0);
> +	}

I'd vote for a /* XXX: Once we have proper pfit state tracking implemented
with hw state read/check support we should switch to only disable the pfit
when we know it's used */

The idea is that the power well code here irks me a bit, after all if
something is on and we want to disable it, it can't be also off due to the
power well being down ;-)
-Daniel

>  
>  	intel_ddi_disable_pipe_clock(intel_crtc);
>  
> -- 
> 1.7.10.4
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch