Messages in this thread | | | Date | Mon, 14 Apr 2008 19:19:04 +0200 | From | (Joerg Schilling) | Subject | Re: Again... DMA speed too slow |
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Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> On Mon, 14 Apr 2008 18:54:22 +0200 > Joerg.Schilling@fokus.fraunhofer.de (Joerg Schilling) wrote: > > > >Which controller are you on? I bet the recording itself will work fine > > >on 48x. It's probably that READ/WRITE BUFFERs are executed using PIO > > >for compatibility reasons. > > > > If this happens inside Linux, Linux should be changed... > > The cases Linux falls back to PIO are the cases where the hardware isn't > up to it, or reliably handling some DMA commands. Lots of that about in > the PC world.
OK, I know that a few drives give wrong DMA speed test results on Solaris, so the behavior for these drives seems to be unrelated to the OS.
Cdrecord is under constant development and for this reason, there are workareounds for these drives.
> > 2.01.01a38 is the latest. Install cdrecord suid root > > Remarkably brave ;)
I am not sure why you mention the term "brave", is it because all known Linux distributions still require suid root? In this case, I encourage you to inform yourself about the code quality of cdrecord. There was no known security problem during the past 4 years. Try to compare with other software ,-)
If you have problems with drives that implement no DMA with read buffer, just call:
CDR_FORCESPEED=any cdrecord ......
Another way to deal with the problem is to create a file /etc/default/cdrecord and to configure to use burnfree by default for the related drive.
e.g. by using a line:
optiarc= 1,0,0 -1 -1 burnfree
and call "cdrecord dev=optiarc ..."
If there is interest in having a way to force any speed without swiching on burnfree, I may add an option that may be used in /etc/default/cdrecord with the same effect as CDR_FORCESPEED=any
Jörg
-- EMail:joerg@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin js@cs.tu-berlin.de (uni) schilling@fokus.fraunhofer.de (work) Blog: http://schily.blogspot.com/ URL: http://cdrecord.berlios.de/old/private/ ftp://ftp.berlios.de/pub/schily -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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