[linux-audio-user] Disabling cardbus prefetch for Echo Indigo

Jon Stutters jonathan.stutters at ntlworld.com
Tue Aug 16 10:15:19 EDT 2005


Paul Davis wrote:
> On Tue, 2005-08-16 at 13:34 +0100, Jon Stutters wrote:
> 
>>Hi all,
>>
>>I'm trying to get an Echo Indigo IO working under Gentoo 2.6.12 kernel. 
>>  The card's recognized correctly by ALSA and I can play through it but 
>>all output is badly distorted.
>>
>>I had the same problem on this laptop under Windows and fixed it using a 
>>utility from Echo to disable prefetch for the cardbus chipset (ENE 
>>CB1410).  Does anyone know how to disable prefetch under Linux?  I've 
>>had a go at hacking the cardbus driver source but I've not got the right 
>>result yet.
> 
> i would have thought that this was susceptible to the same kind of
> solution that Ico used to solve a similar problem with the RME HDSP
> pcmcia card. rather than hack the driver, use setpci and its cousins to
> investigate and modify the state of the PCI device registers. you will
> need to find out how to get the state in windows before and after that
> utility runs, and then take the information on what it changed and apply
> it to setpci.

You're a lifesaver Paul thanks very much.

For the record:
To disable prefetch on the ENE CB1410 and fix playback with the Echo 
Indigo IO change C8h to 0200h.  For example:

setpci -s 02:04.0 c8.W=2,0
(where 02:04.0 is the cardbus controller address)

Cheers,
Jon Stutters



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