Re: Multiple errors with DVD drive

[Damien Le Moal <damien.lemoal@opensource.wdc.com>]

On 9/23/22 21:07, J.J. Berkhout wrote:
> 
> 
> On 23-09-2022 00:08, Damien Le Moal wrote:
>> On 9/21/22 21:38, J.J. Berkhout wrote:
>>> 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)
>>
>> What kernel version are you running ? This should work with the latest
>> kernels. Your kernel likely pre-dates the addition of all the ata horkage
>> flag as boot parameter options, which I think was with 5.18 kernel.
> 
> Yep, I run Ubuntu 5.15.0-48-generic kernel.  I circumvented this by
> using sysfsutils with
> 	class/scsi_host/host0/link_power_management_policy = max_performance
> in the /etc/sysfs.conf file.  As long as I don't mess around with my
> hardware, the host number should stay the same.

OK. Then "nolpm" not being a valid parameter is normal then. I wanted to 
make sure there is no bug in the parameters handling :)

> 
> Kind regards,
> 
> Jaap Berkhout

-- 
Damien Le Moal
Western Digital Research