[RFC PATCH v2] dmabuf-sync: Introduce buffer synchronization framework

[Lucas Stach]

Am Dienstag, den 18.06.2013, 18:04 +0900 schrieb Inki Dae:
[...]
> 
> > a display device driver.  It shouldn't be used within a single driver
> > as a means of passing buffers between userspace and kernel space.
> 
> What I try to do is not really such ugly thing. What I try to do is to
> notify that, when CPU tries to access a buffer , to kernel side through
> dmabuf interface. So it's not really to send the buffer to kernel.
> 
> Thanks,
> Inki Dae
> 
The most basic question about why you are trying to implement this sort
of thing in the dma_buf framework still stands.

Once you imported a dma_buf into your DRM driver it's a GEM object and
you can and should use the native DRM ioctls to prepare/end a CPU access
to this BO. Then internally to your driver you can use the dma_buf
reservation/fence stuff to provide the necessary cross-device sync.

Regards,
Lucas
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