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
hardware.
> >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
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