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

Re: Pioneer DVR-106D issues

> Volker, are you using ide-scsi or ide-cd?

I always use ide-scsi with burners and so far never had trouble with it.
It's also required for Andy's random write patch.

Btw you can change that at run-time by reloading modules ide-cd and
ide-scsi (need to rmmod some other modules first). Both grab all
available devices when loaded, unless you use ignore=hdb,hdd etc on the
first one.

> I'm actually beginning to wonder if the issue is partially my ide cable 
> itself.

Oh wow, they cost 4EUR here (proper high-density ones), at the first
hint of trouble the scissors go through the old one ;))) They are
actually more fragile than one generally assumes, especially as one is
forced to pull them off at the cable instead of at the connector.

> anything to do with the CPU itself.  It very much sounds like a scheduling 
> issue, really, and I'd like to find some other people with the same issue to 

Can't comment, but Linux does seem to have too much trouble with IDE

> >to agree 100% with Andy's assessment of the situation. He gave sound
> >reason for his conclusion. I am still very interested in your detailed
> >technical explanation on why a fast CPU with 0% load only manages a 0.4x
> >DVD burn speed because of a lack of enabled DMA.
> Let me comment this by telling you that I definitely did see exactly this
> behavior on a system that cannot properly do DMA.
> The transferrate (after BurnProof had been enabled) was noticable below 1x,
> the drive was a Pioneer A06.

If you write something which _may_ be right, and of which everyone,
including yourself, expects that it is a very unusual set of
circumstances, it would have helped a lot if you had mentioned that you
have *actually observed* such a ^%@%^#@# system.

> >good sign).  The read speed for the disk ends up topping out at around 3MB/s
> >with the CPU using about 80%-90% CPU time in kernel space.  A test of reading
> >a DVD-R 4x shows around 4.5MB/s with the same CPU usage though a lot more
> >stutter in apps.
> This looks as if there is no DMA :-(

Agreed (unless the test was with readcd -c2scan).

A good way to find out about the effectiveness of DMA is to observe the
cpu load while reading, cat /dev/cdrecorder >/dev/null will do. Toggling
the dma bit with hdparm should cause noticable changes in cpu load.


Volker Kuhlmann			is possibly list0570 with the domain in header
http://volker.dnsalias.net/		Please do not CC list postings to me.

Reply to: