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

Am Dienstag, den 18.06.2013, 18:04 +0900 schrieb Inki Dae:
[...]

quoted

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
-- 
Pengutronix e.K.                           | Lucas Stach                 |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-5076 |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |