[PATCH] drm/vmwgfx: fix lock breakage

[Thomas Hellstrom]

On 10/30/2014 06:39 PM, Rob Clark wrote:
> After:
>
> commit d059f652e73c35678d28d4cd09ab2cec89696af9
> Author:     Daniel Vetter <daniel.vetter at ffwll.ch>
> AuthorDate: Fri Jul 25 18:07:40 2014 +0200
>
>     drm: Handle legacy per-crtc locking with full acquire ctx
>
> drm_mode_cursor_common() was switched to use drm_modeset_(un)lock_crtc()
> which uses full aquire ctx.  So dropping/reaquiring the lock via
> drm_modeset_(un)lock() directly isn't the right thing to do, as lockdep
> kindly points out.
>
> The 'FIXME's about sorting out whether vmwgfx *really* needs to lock-all
> for cursor updates still apply.
>
> Signed-off-by: Rob Clark <robdclark at gmail.com>
Tested-by: Thomas Hellstrom <thellstrom at vmware.com>

Thanks, Rob.

/Thomas


> ---
>  drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
> index d2bc2b0..8fc1e38 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
> @@ -187,7 +187,7 @@ int vmw_du_crtc_cursor_set(struct drm_crtc *crtc, struct drm_file *file_priv,
>  	 * can do this since the caller in the drm core doesn't check anything
>  	 * which is protected by any looks.
>  	 */
> -	drm_modeset_unlock(&crtc->mutex);
> +	drm_modeset_unlock_crtc(crtc);
>  	drm_modeset_lock_all(dev_priv->dev);
>  
>  	/* A lot of the code assumes this */
> @@ -252,7 +252,7 @@ int vmw_du_crtc_cursor_set(struct drm_crtc *crtc, struct drm_file *file_priv,
>  	ret = 0;
>  out:
>  	drm_modeset_unlock_all(dev_priv->dev);
> -	drm_modeset_lock(&crtc->mutex, NULL);
> +	drm_modeset_lock_crtc(crtc);
>  
>  	return ret;
>  }
> @@ -273,7 +273,7 @@ int vmw_du_crtc_cursor_move(struct drm_crtc *crtc, int x, int y)
>  	 * can do this since the caller in the drm core doesn't check anything
>  	 * which is protected by any looks.
>  	 */
> -	drm_modeset_unlock(&crtc->mutex);
> +	drm_modeset_unlock_crtc(crtc);
>  	drm_modeset_lock_all(dev_priv->dev);
>  
>  	vmw_cursor_update_position(dev_priv, shown,
> @@ -281,7 +281,7 @@ int vmw_du_crtc_cursor_move(struct drm_crtc *crtc, int x, int y)
>  				   du->cursor_y + du->hotspot_y);
>  
>  	drm_modeset_unlock_all(dev_priv->dev);
> -	drm_modeset_lock(&crtc->mutex, NULL);
> +	drm_modeset_lock_crtc(crtc);
>  
>  	return 0;
>  }