Re: [PATCH 6/6] drm/i915: get runtime PM at intel_set_mode

From: Daniel Vetter <daniel@ffwll.ch>
To: Paulo Zanoni <przanoni@gmail.com>
Cc: intel-gfx@lists.freedesktop.org, Paulo Zanoni <paulo.r.zanoni@intel.com>
Subject: Re: [PATCH 6/6] drm/i915: get runtime PM at intel_set_mode
Date: Sat, 8 Mar 2014 11:04:06 +0100	[thread overview]
Message-ID: <20140308100406.GI25837@phenom.ffwll.local> (raw)
In-Reply-To: <1394233524-3522-7-git-send-email-przanoni@gmail.com>

On Fri, Mar 07, 2014 at 08:05:24PM -0300, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni@intel.com>
> 
> Otherwise, when we run intel_modeset_check_state we may already be
> runtime suspended, and our state checking code will read registers
> while the device is suspended. This can only happen if your
> autosuspend_delay_ms is low (not the default 10s) and i915.pc8_timeout
> is set to zero.
> 
> NOTE: The correct way to fix this problem would be to properly get/put
> runtime PM at the get_config/state functions. I still didn't do this,
> so I'll keep this patch on the series because it fixes the remaining
> WARNs we get while running the pm_pc8 test suite. It's fine if we
> don't merge this. The problem

Imre has added a bunch more power well enabling checks ... do we still
have gaps in our coverage?

If it's not a terrible lot of them I'd prefer we properly close those
instead of this little hack here. So still not too happy to merge this ;-)
-Daniel

> 
> v2: - Add the note above.
> 
> Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 0868afb..dc2b377 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -9785,13 +9785,18 @@ static int intel_set_mode(struct drm_crtc *crtc,
>  			  struct drm_display_mode *mode,
>  			  int x, int y, struct drm_framebuffer *fb)
>  {
> +	struct drm_device *dev = crtc->dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
>  	int ret;
>  
> +	intel_runtime_pm_get(dev_priv);
> +
>  	ret = __intel_set_mode(crtc, mode, x, y, fb);
>  
>  	if (ret == 0)
>  		intel_modeset_check_state(crtc->dev);
>  
> +	intel_runtime_pm_put(dev_priv);
>  	return ret;
>  }
>  
> -- 
> 1.8.5.3
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch