[Intel-gfx] [PATCH 3/7] drm/i915: don't read pp_ctrl_reg if we're suspended

[Daniel Vetter]

On Tue, Apr 01, 2014 at 02:55:09PM -0300, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
> 
> ... at edp_have_panel_vdd. Just return false, saying we don't have the
> panel VDD since the device is suspended.
> 
> We started getting WARNs about this problem since the patch that
> started checking if we're suspended while reading registers.
> 
> Testcase: igt/pm_pc8
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>

Hm, where's an example backtrace for this? I wonder whether we simply need
to extend the range where we hold the runtime pm ref a bit ...

Whatever, merged (I can rebase afterwards if you supply the backtrace for
the commit message, there we should at least have it).
-Daniel
> ---
>  drivers/gpu/drm/i915/intel_dp.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 6f767e5..44471cc 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -314,7 +314,8 @@ static bool edp_have_panel_vdd(struct intel_dp *intel_dp)
>  	struct drm_device *dev = intel_dp_to_dev(intel_dp);
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  
> -	return (I915_READ(_pp_ctrl_reg(intel_dp)) & EDP_FORCE_VDD) != 0;
> +	return !dev_priv->pm.suspended &&
> +	       (I915_READ(_pp_ctrl_reg(intel_dp)) & EDP_FORCE_VDD) != 0;
>  }
>  
>  static void
> -- 
> 1.8.5.3
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch