The 40 wire detect (forcing the host to DMA2) is a good start. I am
researching the implications to our setup. Thanks for the help
Best wishes,
John
From: Doug Maxey <dwm@xxxxxxxxxxxxxx>
To: "John Treubig" <jtreubig@xxxxxxxxxxx>
CC: jeff@xxxxxxxxxx, linux-scsi@xxxxxxxxxxxxxxx, linux-ide@xxxxxxxxxxxxxxx
Subject: Re: Controlling PATA access speeds
Date: Thu, 01 Jun 2006 16:21:58 -0500
On Thu, 01 Jun 2006 15:35:23 CDT, "John Treubig" wrote:
>Jeff,
>
>You bring up a good point in the fact that I believe your refering to
>detecting 80 wire vs. 40 wire. We've not tried to use this to our
>advantage, but it could have some merrit. What does the driver do if it
>encounters a 40 wire cable and the drive says it's capable of DMA5?
>
The presence of a 40 wire cable limits the device to UDMA2 - 33mhz.
See the ATA6 or later on t13.org.
JS20 blades are lackinging the strapping to indicate the devices hanging
off the amd8111 are on the equivalent of 80 wire - 4 inch trace on mb.
In the JS20 case, a quirk will be necessary to run at speeds higher than
UDMA2.
++doug
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