Re: Multiple errors with DVD drive

[Niklas Cassel <Niklas.Cassel@wdc.com>]

On Wed, Sep 21, 2022 at 12:28:34PM +0200, J.J. Berkhout wrote:
> On 20-09-2022 23:08, Niklas Cassel wrote:
> >
> > You should be able to test this theory by adding libata.force=nolpm
> > on the kernel command line on a recent (non-working) kernel, low power
> > modes should then be disabled, and the drive should work again.
> > (You can press 'e' in grub to temporarily add something to the kernel
> > command line, and then ctrl+x to boot.)
> >
> > But the proper fix is probably to add a quirk for you device, either:
> > +       { "PIONEER BD-RW   BDR-207M",   NULL,   ATA_HORKAGE_NOSETXFER },
> > or
> > +       { "PIONEER BD-RW   BDR-207M",   NULL,   ATA_HORKAGE_NOLPM },
>
> I just tested the libata.force=nolpm kernel parameter on my system
> running kernel 5.15.0-48-generic x86_64 (linux mint 20.3, base Ubuntu
> 20.04 focal).  I am sorry to say, this parameter did not solve the problem.

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".

However, disabling all low power modes on the kernel command line
should basically be the same.


Perhaps you could verify that your policy is "max_performance" out of the box
when booting the non-working kernel with libata.force=nolpm.

Booting the non-working without libata.force=nolpm should result in
"med_power_with_dipm"
(as that is the ubuntu default).

Booting the old kernel should result in "max_performance", since lpm
wasn't available/allowed for your AHCI controller in your old kernel.


>
> As for your patch concerning NOSETXFER, I will try to test this shortly,
> but it could take one or two days (medical stuff for me and my wife).

There is absolutely no need to rush.


Kind regards,
Niklas