[Intel-gfx] [PATCH v2] drm/i915: fix suspend/resume for GENs w/o runtime PM support

[Daniel Vetter]

On Tue, Aug 26, 2014 at 01:26:56PM +0300, Imre Deak wrote:
> Before sharing common parts between the system and runtime s/r
> handlers we WARNed if the runtime s/r handlers were called on GENs that
> didn't support RPM. But this WARN is not correct if the same handler is
> called from the system s/r path, since that can happen on any platform.
> This also broke system s/r on old platforms.
> 
> The issue was introduced in
> 
> commit 016970beb05da6285c2f3ed2bee1c676cb75972e
> Author: Sagar Kamble <sagar.a.kamble at intel.com>
> Date:   Wed Aug 13 23:07:06 2014 +0530

Aside: I just realized that this patch adds an rpm_resume paramter to the
platform resume functions. Somehow I've been blind and didn't spot that
one. Not a good idea imo, since that still means we have piles of
arbitrary differences between the different platforms and code paths.

> v2:
> - remove the WARN and depend on the HAS_RUNTIME_PM check in
>   rutime_suspend/resume instead (Daniel)
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=82751
> Signed-off-by: Imre Deak <imre.deak at intel.com>

Queued for -next, thanks for the patch.
-Daniel

> ---
>  drivers/gpu/drm/i915/i915_drv.c | 31 ++++++++++++++-----------------
>  1 file changed, 14 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index de1b664..b5fd1c5 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1412,7 +1412,9 @@ static int intel_runtime_suspend(struct device *device)
>  	if (WARN_ON_ONCE(!(dev_priv->rps.enabled && intel_enable_rc6(dev))))
>  		return -ENODEV;
>  
> -	WARN_ON(!HAS_RUNTIME_PM(dev));
> +	if (WARN_ON_ONCE(!HAS_RUNTIME_PM(dev)))
> +		return -ENODEV;
> +
>  	assert_force_wake_inactive(dev_priv);
>  
>  	DRM_DEBUG_KMS("Suspending device\n");
> @@ -1480,7 +1482,8 @@ static int intel_runtime_resume(struct device *device)
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	int ret;
>  
> -	WARN_ON(!HAS_RUNTIME_PM(dev));
> +	if (WARN_ON_ONCE(!HAS_RUNTIME_PM(dev)))
> +		return -ENODEV;
>  
>  	DRM_DEBUG_KMS("Resuming device\n");
>  
> @@ -1515,16 +1518,12 @@ static int intel_suspend_complete(struct drm_i915_private *dev_priv)
>  	struct drm_device *dev = dev_priv->dev;
>  	int ret;
>  
> -	if (IS_GEN6(dev)) {
> -		ret = 0;
> -	} else if (IS_HASWELL(dev) || IS_BROADWELL(dev)) {
> +	if (IS_HASWELL(dev) || IS_BROADWELL(dev))
>  		ret = hsw_suspend_complete(dev_priv);
> -	} else if (IS_VALLEYVIEW(dev)) {
> +	else if (IS_VALLEYVIEW(dev))
>  		ret = vlv_suspend_complete(dev_priv);
> -	} else {
> -		ret = -ENODEV;
> -		WARN_ON(1);
> -	}
> +	else
> +		ret = 0;
>  
>  	return ret;
>  }
> @@ -1540,16 +1539,14 @@ static int intel_resume_prepare(struct drm_i915_private *dev_priv,
>  	struct drm_device *dev = dev_priv->dev;
>  	int ret;
>  
> -	if (IS_GEN6(dev)) {
> +	if (IS_GEN6(dev))
>  		ret = snb_resume_prepare(dev_priv, rpm_resume);
> -	} else if (IS_HASWELL(dev) || IS_BROADWELL(dev)) {
> +	else if (IS_HASWELL(dev) || IS_BROADWELL(dev))
>  		ret = hsw_resume_prepare(dev_priv, rpm_resume);
> -	} else if (IS_VALLEYVIEW(dev)) {
> +	else if (IS_VALLEYVIEW(dev))
>  		ret = vlv_resume_prepare(dev_priv, rpm_resume);
> -	} else {
> -		WARN_ON(1);
> -		ret = -ENODEV;
> -	}
> +	else
> +		ret = 0;
>  
>  	return ret;
>  }
> -- 
> 1.8.4
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch