Limit SATA link speed to 1.5 Gbps

Limit SATA link speed to 1.5 Gbps

[Andre Pietsch]

Hi,

I hope this is not OT or not allowed to post here as there might be better places elsewhere. I STW and read the FAQ but did not find something that forbids it.

I own a DELL Vostro 1700 with
ICH8
2 x ST980813ASG, 80GB SATA drive.

Many times the disk produces ATA bus errors and "hard resetting link" appear in the log. While this happens the system hangs (Ubuntu 8.0.4).

In the past it resetted the link 3.0 Gbps and a few minutes later ATA bus errors and "hard resetting link" appear again.

I tested 2.6.25 and the error still occurrs once but then it gave me a "limiting SATA link speed to 1.5 Gbps" in the log.

After that the error does not show again for this boot.

Going back to 2.6.24 it shows the same behaviour now (very odd, since SATA control seems to be kernel specific to me).

All good one could think, but
1) I need to reinstall, since I would like to install 64Bit Ubuntu (currently 32Bit) and
2) I do not know if I can reproduce that "fix".

Is it possible to set the SATA link speed somewhere?

For a dmesg log see here
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/196076/comments/20

This bug report was opened when I thought this was a drive specific NCQ issue...

I still do not what the cause is but having the interface running at 1.5 Gbps stable would be sufficient for me.

Regards,
Andre Pietsch, SCAI GmbH 

Re: Limit SATA link speed to 1.5 Gbps

[Alan Cox]

> I tested 2.6.25 and the error still occurrs once but then it gave me a "limiting SATA link speed to 1.5 Gbps" in the log.

The later kernels will drop the SATA speed on repeated errors if they see
what appears to be a consistent problem that might be cabling/noise.

> Is it possible to set the SATA link speed somewhere?

Not sure. I've not looked whether that is in the new "force" code. I
don't think you can in 2.6.24 however, and 2.6.25 will fall back nicely.

Other than being annoying during the install it should not cause any
other problems beyond all the retries.

Re: Limit SATA link speed to 1.5 Gbps

[Andre Pietsch]

> > I tested 2.6.25 and the error still occurrs once but then it gave me
a "limiting SATA link speed to 1.5 Gbps" in the log.
> 
> The later kernels will drop the SATA speed on repeated errors if they
see what appears to be a consistent problem that might be cabling/noise.
> 
> > Is it possible to set the SATA link speed somewhere?
> 
> Not sure. I've not looked whether that is in the new "force" code. I
don't think you can in 2.6.24 however, and 2.6.25 will fall back nicely.
> 
> Other than being annoying during the install it should not cause any
other problems beyond all the retries. 

Hi Alan,

thanks for your input. I can report that Ubuntu 8.0.4 64 does behave the
same way as the 32 Bit version and limits the link speed successfully,
after the link fails several times.

After this the errors do not occurr any more.

This works for me now. I'll update the bug report on launchpad.

Regards,
Andre Pietsch

RE: Limit SATA link speed to 1.5 Gbps-

[Andre Pietsch]

Alan & others,

> > Is it possible to set the SATA link speed somewhere?
> 
> Not sure. I've not looked whether that is in the new "force" 
> code. I don't think you can in 2.6.24 however, and 2.6.25 
> will fall back nicely.
> 
> Other than being annoying during the install it should not 
> cause any other problems beyond all the retries.
> 
SOLVED
On Seagate drives it is possible to limit the link speed by setting a
jumper on the drive! It now starts at 1.5 Gbps and runs stable from the
start.

Thanks everybody for your support!

Regards,
Andre Pietsch