Re: CVS commit: src/sys/dev/ieee1394

[KIYOHARA Takashi <kiyohara%kk.iij4u.or.jp@localhost>]

Hi! tsutsui-san,


From: Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>
Date: Sun, 30 Apr 2006 23:14:18 +0900

> > Log Message:
> > Remove sync-ope for descritor of DMA, because its descriptor set
> > BUS_DMA_COHERENT flag.
> 
> BUS_DMA_COHERENT is just a hint (i.e. not provided on all architectures)
> and sync ops would handle other stuff than cache sync (xfer data from/to
> bounce buffer etc.), so you can't remove sync ops even if BUS_DMA_COHERENT
> is specified.
> (MD sync ops may return without cache sync if COHERENT flag is set anyway)

hmm...
The ieee1394 driver's DMA descriptor cannot be operated if it is not a
memory of coherent now.  This is because processing that rewrites
descriptor without stopping DMA under operation is done. 

In that case, ieee1394 today will not be able to be used.  Is there
something any idea?

Thanks,
--
kiyohara