Subject: Re: CF/IDE performance problem...
To: None <>
From: Warner Losh <>
List: tech-kern
Date: 11/22/2005 23:19:58
>   The current CF specification requires mode reporting, and also requires
> the device to not report DMA capability if the DMARQ line is not
> connected.

As someone who deals with CF on a daily basis in many different
products, I can tell you that there are many CF cards that do report
DMA capability when DMARQ isn't connected on old CF<->IDE adapters.
This leads to lots of failures when DMA is enabled by the host (either
BIOS or OS).  These cards are non-conformant, since the IDE adapters
do not have DMARQ connected (newer ones do, however).  Relying on this
part of the spec being implemented correctly is asking for trouble.