# [SOLVED!] HDParm DMA problem: Operation not permitted

## Phk

Hi there people.... Sorry to re-bother you about this kind of problems, but i've read the related posts and still can't fix this up!!!

My HDD doesn't accept DMA in the 2.6 kernels, however, the whole thing works fine when booting the liveCD, but now, no DMA for me =(

I'll go directly to printscreens  :Wink: 

hdparm -tT /dev/hda

 *Quote:*   

> /dev/hda:
> 
>  Timing buffer-cache reads:   1524 MB in  2.00 seconds = 761.35 MB/sec
> 
>  Timing buffered disk reads:   18 MB in  3.19 seconds =   5.63 MB/sec

 

(see? 5MB/sec? on a P4 laptop? NO WAY!)

/etc/conf.d/hdparm: (yes, i've rc-updated it!)

 *Quote:*   

> all_args="-k1K1d1c3u1S242A1m16 -X66 -a2048"

 

if i type:

 *Quote:*   

> # hdparm -k1K1d1c3u1S242A1m16 -X66 -a2048 /dev/hda
> 
> /dev/hda:
> 
>  setting fs readahead to 2048
> ...

 

Another important notice:

 *Quote:*   

> # lspci | grep IDE
> 
> 00:02.5 IDE interface: Silicon Integrated Systems [SiS] 5513 [IDE]

 

And this is the driver enabled in the Kernel.... (2.6.5-hardened-r3)

PLEASE could any expert help me about this? Please?  :Wink: 

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## Purrkur

Why are you so sure that the performance of your drive is any better than that?

Btw, you forgot to include info on your harddisk make and model.

Phew, I have never seen such a loaded hdparm statement. Are you sure you are not slowing it down by asking something of it that it doesn't have?? Haven't you heard of the term "Less is more"?  :Wink: 

I am also using a computer that has the SIS 5513 IDE interface and DMA works just fine on it. I only have the "-d1" parameter set and after playing around with your parameters for a bit, I was only able to raise performance marginally. Fwiw, I would personally not include k1 and K1 (are you sure your drive supports it?).

Anyhow, you should also know that hard drives in laptops are always slow as hell. They usually only turn at 4200 rpm (although 5400 rpm disks are beginning to pop up everywhere, but that is still dog-slow) and they are also built to run on battery (that is, using as little current as possible) instead of performance. I don't have my work laptop with me here at home but I remember also getting extremely poor performance out of it when doing some tests. 

Don't get stuck on those figures. They don't mean much because your computer is always using the cache on the drive anyways which conseals the real slowness of the drive. If you want real harddisk performance, get a real desktop with SCSI disks....

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## Liquidcz

Sorry about OT, where can i find parameter which i can use for my HDD?

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## Purrkur

Liquidcz,

Try "man hdparm". Then you should read up on your harddrive specification and see what it supports. Doing "hdparm -i /dev/hda" will help you out some....

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## nahpets

check out  this thread.  I had the same problem, and removing "generic IDE support" in my kernel options did the trick.  I went from 3 MB/s to 50.

If you still can't get it to work, try booting from KNoppix and see what drivers it uses.

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## Phk

 *nahpets wrote:*   

> check out  this thread.  I had the same problem, and removing "generic IDE support" in my kernel options did the trick.  I went from 3 MB/s to 50.
> 
> If you still can't get it to work, try booting from KNoppix and see what drivers it uses.

 

Solved!! Removing Generic IDE Support solved the issue.. Thankx a lot to both! [[ ]]

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