Unable to enable DMA on some AMD systems

Christoph Wiesen chris at deadhand.com
Sun Jun 5 12:39:15 CDT 2005

Am Sonntag 05 Juni 2005 15:53 schrieb Thomas Hofer:
> My solution was to insert "amd74xx" as first line into /etc/modules and
> reboot.

Now look there,

what me and Google couldn't solve in several hours of investigation you did in 
one sentence. Thank you, Thomas!

I actually did several attempts at /etc/modules. But I learned two things 
here: Happily appending everything at the *end* of the file isn't always the 
best thing to do. And second: I should take a minute and consider what the 
changed config file will actually *do*... oh my.

All things done I'm almost there. Now I can enable DMA with hdparm for both my 
DVD drives.
The module in question was actually "via82cxxx" and not "amd74xx" - so the 
issue is not limited to a specific chipset or module it seems, no idea why 
some (or many) with apparently similar systems do not have these troubles.

Back on topic I still have to enable hdparm manually. Can you tell me as well, 
how I can automate this? I'd rather not have to use hdparm inside a script 
(though I'd like to hear about this as well if theres no other way). I 
thought there was a way to tell the system to always try to use DMA if 

Thanks again for the quick help, this is, well... a lot better than compiling 
my own kernel ;)

Kind regards,


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