Re: Multiple errors with DVD drive

J.J. Berkhout
2022-09-21T12:39:25Z

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Hello,

On 21-09-2022 13:58, Niklas Cassel wrote:
> Another way do disable lpm is to do:
>
> $ ls -al /sys/class/scsi_host/host*
>
> Find your device in the list. My device is:
> /sys/class/scsi_host/host13/
>
> Print the current lpm policy for your device:
> $ cat /sys/class/scsi_host/host13/link_power_management_policy
> med_power_with_dipm
>
> Anything other than "max_performance" means that you have (a varying degree)
> of low power modes enabled.
>
> $ sudo sh -c "echo max_performance > /sys/class/scsi_host/host13/link_power_management_policy"
>
> $ cat /sys/class/scsi_host/host13/link_power_management_policy
> max_performance
>
> Try reading from the optical drive after ensuring that the policy is
> "max_performance".
>

Yes, this worked and did the trick! Reading without any errors. I did
not yet try to write, but will do so today.
When booting with libata.force=nolpm the link_power_management_policy
was still med_power_with_dipm and I got the dmesg:

[ 0.291452] ata: failed to parse force parameter "nolpm" (unknown value)

so the ineffectiveness of this boot parameter seems to be explained.
Might there be some other syntax for this parameter?

Nevertheless, my problem now has a work-around and I am very happy.
Thanks, Niklas.

Kind regards,

Jaap Berkhout