Re: [RFC][PATCH 0/2] dma-buf: add importer private data for reimporting

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Am Freitag, den 31.05.2013, 17:29 +0200 schrieb Daniel Vetter:
> On Fri, May 31, 2013 at 07:22:24PM +0900, 김승우 wrote:
> > Hello Daniel,
> > 
> > Thanks for your comment.
> > 
> > On 2013년 05월 31일 18:14, Daniel Vetter wrote:
> > > On Fri, May 31, 2013 at 10:54 AM, Seung-Woo Kim <sw0312.kim@xxxxxxxxxxx> wrote:
> > >> importer private data in dma-buf attachment can be used by importer to
> > >> reimport same dma-buf.
> > >>
> > >> Seung-Woo Kim (2):
> > >>   dma-buf: add importer private data to attachment
> > >>   drm/prime: find gem object from the reimported dma-buf
> > > 
> > > Self-import should already work (at least with the latest refcount
> > > fixes merged). At least the tests to check both re-import on the same
> > > drm fd and on a different all work as expected now.
> > 
> > Currently, prime works well for all case including self-importing,
> > importing, and reimporting as you describe. Just, importing dma-buf from
> > other driver twice with different drm_fd, each import create its own gem
> > object even two import is done for same buffer because prime_priv is in
> > struct drm_file. This means mapping to the device is done also twice.
> > IMHO, these duplicated creations and maps are not necessary if drm can
> > find previous import in different prime_priv.
> 
> Well, that's imo a bug with the other driver. If it doesn't export
> something really simple (e.g. contiguous memory which doesn't require any
> mmio resources at all) it should have a cache of exported dma_buf fds so
> that it hands out the same dma_buf every time.

I agree with the reasoning here.

Though it would be nice to have this "expected driver behavior" put down
somewhere in the documentation. Any volunteers?

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 |

--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Input]     [Video for Linux]     [Gstreamer Embedded]     [Mplayer Users]     [Linux USB Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [Yosemite Backpacking]
  Powered by Linux