# no DMA?!?

## mrspam

Hi!

I have a problem activating DMA for my attached IDE-devices. I have a Abit AG8 with serial ata and a single IDE-Connector. The SATA-disk just works fine but the two ide-devices just hang (no, the whole system hangs! -> P4, 3.2Ghz, 1GB Ram) on any action due to the lack of dma activation.

I tried the kernels 2.6.7-r14, 2.6.8-r4 and 2.6.9-rc1-mm4. Always the same result...

sda: Seagate SATA

hdc: Seagate IDE

hdd: Nec DVD-RW

if I try to activate DMA

hdparm -d 1 /dev/hdc

 *Quote:*   

> /dev/hdc:
> 
>  setting using_dma to 1 (on)
> 
>  HDIO_SET_DMA failed: Operation not permitted
> ...

 

but using the -i switch

 *Quote:*   

> hdparm -i /dev/hdc
> 
> /dev/hdc:
> 
>  Model=ST3200822A, FwRev=3.01, SerialNo=3LJ1KRH0
> ...

 

it seems that any DMA modes are available.

Here is lspci output:

 *Quote:*   

> # lspci -v
> 
> 0000:00:00.0 Host bridge: Intel Corp. 915G/P/GV Processor to I/O Controller (rev 04)
> 
>         Subsystem: ABIT Computer Corp.: Unknown device 1032
> ...

 

I activated the Intel PIIX/ICH SATA Support for SATA and Intel PIIXn chipsets support for IDE.

I just found some articles about this problem but the solution (to go back to kernel 2.6.7) does not work for me   :Sad: 

Any ideas?

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## Gentii

Same problems here. I saw too on lkml there wasn't any problem with 2.6.7, but it does the same.

I got 2 sata drives and one ide dvd burner :

sda,sdb: sata drives

hda : dvd burner.

And I can't enable dma on hda. After reading the few threads about it here, I thought it was a conflict between ide and sata intel drivers, as you mentionned it. But it isn't !

I switched my both sata drivers to my promise controller, and it's still the same.

The sata intel drivers aren't even enabled in the kernel, only the ide one is (piix) and it still doesn't work. Someone has to do a bug report, if there isn't already one, because we are many affected by the problem.

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## mrspam

Gentii, if you are using a scsi driver (-emulation) for your sata drives, you cannot enable dma becaue scsi doesn't support dma.

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## Gentii

well, it's normal for the sata drives. But for my ide cdrom, it shouldnt be using scsi emulation, does it?

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## mikepolniak

Just to confirm that i can set DMA with Kernel 2.6.7 but not with 2.6.9-rc1 on my SATA Raptor. I have 2 systems, one using the PIIx contoller controller and one using the SII controller. These are IDE not scsi (libata) drivers.

So i think its a kernel ide problem.

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## ck42

Only interested in this because I'm about to convert to a SATA drive system.  I read somewhere else that if you use the IDE-SATA drivers in the kernel (which say its deprecated) you can enable DMA.

But I've also heard that the SCSI-SATA drivers are more mature/stable?

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## Gentii

Well I read that too, but I don't understand shit. I let the scsi-sata drivers for my promise controller, and I enabled the ide sata driver, which should conflict with the scsi sata drivers, but it seems to work though, nearly the same performance. And I'm now able to enable dma for my ide cdrom drive...

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## baak6

I have the same problem, Intel IDE/SATA chipset...SATA works fine but I get that same error when setting DMA = 1 on my CD-ROM...I believe it's a conflict with the drivers but I'm sure they'll fix it soon...I thought it'd be fixed in 2.6.9 though...but it wasn't.  :Sad: 

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## Treo

Hi,

sadly, same problem here... two SATA drives with SCSI drivers (the IDE SATA drivers don't support my DMA anymore since 2.6.8... 2.6.7 was fine)... the SCSI drivers work fine, and I think I have some reasonable speeds on /dev/sd(a/b):

Timing cached reads:   3924 MB in  2.00 seconds = 1962.30 MB/sec

Timing buffered disk reads:  164 MB in  3.02 seconds =  54.31 MB/sec

But I have huge issues with the IDE part and my CDROM/DVD Multiburner... no DMA support...

I just hope someone fixes this soon... not that I use my cd drive a whole lot... but I want it working...

Treo

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## Gentii

 *Treo wrote:*   

> Hi,
> 
> sadly, same problem here... two SATA drives with SCSI drivers (the IDE SATA drivers don't support my DMA anymore since 2.6.8... 2.6.7 was fine)...
> 
> Treo

 

WTF does that mean ? Sorry but this story of scsi and ide is confusing as hell.

You need the scsi libata driver for your sata drives. So what do you mean with no dma support ?

If you are using the scsi driver, you can't enable dma. And its fast though isn't it ?

And you need to enable the IDE Sata driver (the deprecated one), if you want to enable dma on your cdrom. I still don't understand why do you need a SATA driver for enabling dma on an ide cdrom drive. But it's working so ...

If someone is able to really clear up the thing, and explain why this option is needed, please do it Bug in kernel ? Feature ? What ?

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