[PATCH] drm/vmwgfx: fix lock breakage

[Jakob Bornecrantz]

On Thu, Oct 30, 2014 at 6:40 PM, Rob Clark <robdclark at gmail.com> wrote:
> On Thu, Oct 30, 2014 at 1:39 PM, Rob Clark <robdclark at gmail.com> 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.
>>
>
> Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1155825
>
>> Signed-off-by: Rob Clark <robdclark at gmail.com>
>> ---
>>  drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 8 ++++----
>>  1 file changed, 4 insertions(+), 4 deletions(-)

Reviewed-by: Jakob Bornecrantz <jakob at vmware.com>

>>
>> 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;
>>  }
>> --
>> 1.9.3
>>
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