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Re: [OCLUG-Tech] dma in Ubuntu?

Ah, my bad. :)

* Robert Echlin <rob [ dot ] echlin [ at ] rocketmail [ dot ] com> [091018 11:32]:
> Hi Bart,
> Thanks for the notes on sdparm. I didn't know about that.
> 
> However, it was my system that found the dvd under /dev/scd0
> John was trying to access it as /dev/hda.
> 
> Rob
> 
> 
> 
> 
> ________________________________
> From: Bart Trojanowski <bart-oclug [ at ] jukie [ dot ] net>
> To: Prof. John C Nash <nashjc [ at ] uottawa [ dot ] ca>; linux [ at ] lists [ dot ] oclug [ dot ] on [ dot ] ca
> Sent: Sun, October 18, 2009 10:58:27 AM
> Subject: Re: [OCLUG-Tech] dma in Ubuntu?
> 
> John,
> 
> hdparm is really meant for devices that are driven by ide and legacy ata
> drivers.  If your cdrom shows up as /dev/scd0, then it's going through a
> subsystem of the Linux kernel that's responsible for SCSI.  More
> specifically you're driving your cdrom with "libata" SCSI layer that
> makes IDE/ATA devices look like SCSI ones.  Even though the device
> accepts ATA commands, hdparm doesn't know how to talk to it because the
> kernel didn't git it a device that looks like an ATA device.
> 
> You probably want to look at the sdparm and sg3-utils packages.  Have a
> look at this to learn more about sdparm:
> 
>         http://sg.danny.cz/sg/sdparm.html
> 
> When I last had to use it, I found sdparm a lot harder to figure out
> than the hdparm counter part.  I don't have an ATA CDROM anywhere so I
> was unable to actually generate the command you need to flip DMA on.
> Should you end up using sdparm to get this going, I'd like to learn from
> your success.
> 
> -Bart
> 
> -- 
>                 WebSig: http://www.jukie.net/~bart/sig/
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