[ale] Slow CF/Cardbus Read Rate

[Greg Freemyer]

Looks like the kernel does not support DMA for that device.

How old is the kernel?  Can you upgrade?

On Wed, Feb 18, 2009 at 3:27 PM, Jeff Hubbs <jeffrey.hubbs at gmail.com> wrote:
> That's entirely possible...but here's what happens when I try to set it:
>
> # hdparm -d1 /dev/hda
>
> /dev/hda:
>  setting using_dma to 1 (on)
>  HDIO_SET_DMA failed: Operation not permitted
>  using_dma     =  0 (off)
>
>
>
> On Wed, Feb 18, 2009 at 3:07 PM, Greg Freemyer <greg.freemyer at gmail.com> wrote:
>>
>> Jeff,
>>
>> At that speed, I suspect your using PIO mode not DMA.
>>
>> You may be able to fix it via hdparm.
>>
>> Or you may need to use a newer kernel.
>>
>> Or even 2.6.29 may not have DMA support for the card in question.
>>
>> Greg
>>
>> 2009/2/18 Jeff Hubbs <jeffrey.hubbs at gmail.com>:
>> > I've got a thin client here that's using a purportedly 30MB/s Sandisk CF
>> > card in a CardBus/CF adapter, but I'm only getting 3.0MB/s reads as measured
>> > by both dd and hdparm.  Any way I can speed that up?
>> >
>> > - Jeff
>> >
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>> >
>> >
>>
>>
>>
>> --
>> Greg Freemyer
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-- 
Greg Freemyer
Litigation Triage Solutions Specialist
http://www.linkedin.com/in/gregfreemyer
First 99 Days Litigation White Paper -
http://www.norcrossgroup.com/forms/whitepapers/99%20Days%20whitepaper.pdf

The Norcross Group
The Intersection of Evidence & Technology
http://www.norcrossgroup.com