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

From: Daniel Vetter
Date: Mon May 12 2014 - 04:10:58 EST


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@xxxxxxx>

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

Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> ---
> 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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