linux-kernel - Re: [PATCH 1/2] drm/ast: Fix double lock at PM resume

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Message-ID: <20140512081047.GC25056@phenom.ffwll.local>
Date:	Mon, 12 May 2014 10:10:47 +0200
From:	Daniel Vetter <daniel@...ll.ch>
To:	Takashi Iwai <tiwai@...e.de>
Cc:	David Airlie <airlied@...ux.ie>,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] drm/ast: Fix double lock at PM resume

On Fri, May 09, 2014 at 08:14:14AM +0200, Takashi Iwai wrote:
> The recent commit [3ea87855: drm/helper: lock all around force mode
> restore] introduced drm_modeset_lock_all() in
> drm_helper_resume_force_mode() itself, while ast driver still takes
> this lock before calling it.  Remove the caller side lock for avoid a
> fatal deadlock.
> 
> Signed-off-by: Takashi Iwai <tiwai@...e.de>

Oops, failed to do the audit correctly. Thanks for catching this.

Reviewed-by: Daniel Vetter <daniel.vetter@...ll.ch>
> ---
>  drivers/gpu/drm/ast/ast_drv.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
> index 5137f15dba19..27e56dda476d 100644
> --- a/drivers/gpu/drm/ast/ast_drv.c
> +++ b/drivers/gpu/drm/ast/ast_drv.c
> @@ -94,9 +94,7 @@ static int ast_drm_thaw(struct drm_device *dev)
>  	ast_post_gpu(dev);
>  
>  	drm_mode_config_reset(dev);
> -	drm_modeset_lock_all(dev);
>  	drm_helper_resume_force_mode(dev);
> -	drm_modeset_unlock_all(dev);
>  
>  	console_lock();
>  	ast_fbdev_set_suspend(dev, 0);
> -- 
> 1.9.2
> 

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