[Soekris] 4801 CF, NetBSD-current
soren at soekris.com
Thu Oct 21 00:59:30 UTC 2004
Michael J. Slifcak wrote:
> Soren Kristensen wrote:
>> The net4801 on the other hand have a real busmaster ATA controller,
>> the ATA drivers detect that and will try DMA if the CF card reports
>> the capability. But since the net4801 was designed before the new CF
>> spec, the wires are not connected, so you need to disable DMA manually.
>> The next version of the net4801 PCB has already been updated to have
>> those CF DMA wires, they should start shipping in 4-6 weeks.
>> Best Regards,
>> Soren Kristensen
> What upgrade path for existing net4801 PCB users ?
> Will you post a technical addendum to the web site
> (with pictures) describing how to add the DMA lines to the card ?
> [Making the mods yourself will void the warranty, etc.]
Maybe.... If enough ask for it, it's not really something I want to
encourage as it's not that easy as the pin that need to be disconnected
has the PCB wire under the socket.
> Will there be a fulfillment program to swap non-DMA capable net4801
> with DMA capable net4801 ?
It's not really something I view as very important, as the CF ATA
interface already run at 16 Mbyte/sec PIO mode, DMA will only lower the
CPU usage. And anybody who want real disk performance probably already
use a real 2.5" HD which can use Ultra-DMA 33.
> Well it is not Soekris fault - it's fault of CF specifications to
> be incompatible with previous versions.
> Unless you need the DMA speed it's easiest to disable DMA within
> the OS or ask the CF vendors that sell those incompatible cards.
> All CF vendors should be able to help you disabling the feature.
It's not really the CF specs or the CF vendors fault.... We need to
ensure that the ATA drivers know when to use DMA, so I need to study the
specs and drivers to see what can be done. I'm interested to see if I
can get the BIOS to auto detect if it's wired for DMA and then stop the
ATA drivers from trying to use DMA if it's not wired.
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