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Re: [OCLUG-Tech] dma in Ubuntu?

I also have jaunty jackalope.

According to /etc/fstab, this is my DVDROM, which gives me a target for your hdparm command:
----------------
rme@daddy:~$ grep cdrom /etc/fstab
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto,exec,utf8 0       0
rme@daddy:~$ hdparm -d /dev/scd0

/dev/scd0:
 HDIO_GET_DMA failed: Inappropriate ioctl for device
-------------------
My DVD isn't a writer, just a reader.
Also, it isn't SATA, just old-school IDE - is your's SATA?
So, yours seems to need dma and mine doesn't.

However,  SATA DVD's are newish to Linux and support was spotty a year or so ago. My desktop machine at work that has a SATA DVD-writer takes an extra minute ( or two?) to boot up because the Linux OS I was running waits for it to respond to some HD-only query that the DVD-writer is ignoring. 
-> Not sure if it still does this, so I won't name the OS.

Rob

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Rob Echlin, B. Eng.
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http://talksoftware.echlin.ca
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________________________________
From: Prof. John C Nash <nashjc [ at ] uottawa [ dot ] ca>
To: linux [ at ] lists [ dot ] oclug [ dot ] on [ dot ] ca
Sent: Sat, October 17, 2009 6:09:19 PM
Subject: [OCLUG-Tech] dma in Ubuntu?

Recently k3b has been complaining on startup:

   DMA disabled on device HL-DT-ST - DVDRAM GSA-4167B

I'm running Ubunutu Hardy (Jaunty seems to be set up very differently, with different /dev/... for the DVDRW)

When I try

   hdparm -d /dev/hda

I get

/dev/hda:
using_dma     =  0 (off)

Putting in

/dev/hda:
setting using_dma to 1 (on)
HDIO_SET_DMA failed: Operation not permitted
using_dma     =  0 (off)


I've looked on the web, and there is some commentary about enabling dma in the kernel. Yikes -- we shouldn't need regular users to do that.

Any ideas? Or is this a false complaint by k3b.

JN
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