UCSI failing due to probe() getting version 0

UCSI failing due to probe() getting version 0

[Oliver Neukum]

Hi,

I am trying this on a new laptop, but I am getting a result I do not
understand.
ucsi_acpi_probe() is called, but ucsi_register() fails with -ENODEV,
because ucsi->version is 0.

If I dump the ucsi_acpi buffer I get:

00 00 00 00 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

And, frankly I do not understand that. Why have the ACPI device
but show version number 0?

    Regards
        Oliver

Re: UCSI failing due to probe() getting version 0

[Heikki Krogerus]

On Thu, Aug 05, 2021 at 04:04:03PM +0200, Oliver Neukum wrote:
> Hi,
> 
> I am trying this on a new laptop, but I am getting a result I do not
> understand.
> ucsi_acpi_probe() is called, but ucsi_register() fails with -ENODEV,
> because ucsi->version is 0.
> 
> If I dump the ucsi_acpi buffer I get:
> 
> 00 00 00 00 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 
> And, frankly I do not understand that. Why have the ACPI device
> but show version number 0?

Because of BIOS bugs.

Ideally we should be able to rely on the _STA method of the ACPI
device, but unfortunately with UCSI we can't rely on that alone. On
some systems the BIOS claims that the device is enabled (based on
_STA) even when the platform doesn't actually support UCSI at all.

If you remove the check, does the driver work?

Br,

-- 
heikki

Re: UCSI failing due to probe() getting version 0

[Oliver Neukum]

On 11.08.21 15:23, Heikki Krogerus wrote:
Hi,
> Because of BIOS bugs.
>
> Ideally we should be able to rely on the _STA method of the ACPI
> device, but unfortunately with UCSI we can't rely on that alone. On
> some systems the BIOS claims that the device is enabled (based on
> _STA) even when the platform doesn't actually support UCSI at all.
>
> If you remove the check, does the driver work?

Unfortunately, no it does not:

[    4.657715] ACPI Error: No handler for Region [ECSI]
(00000000862594d8) [EmbeddedControl] (20210604/evregion-135)
[    4.657734] ACPI Error: Region EmbeddedControl (ID=3) has no handler
(20210604/exfldio-265)
[    4.657754] ACPI Error: Aborting method \_SB.UBTC.ECWR due to
previous error (AE_NOT_EXIST) (20210604/psparse-531)
[    4.658812] ACPI Error: Aborting method \_SB.UBTC._DSM due to
previous error (AE_NOT_EXIST) (20210604/psparse-531)
[    4.659646] ACPI: \_SB_.UBTC: failed to evaluate _DSM (0x6)
[    4.659657] ucsi_acpi USBC000:00: ucsi_acpi_dsm: failed to evaluate
_DSM 1
[    4.659665] ucsi_acpi USBC000:00: failed to reset PPM!
[    4.659683] ucsi_acpi USBC000:00: PPM init failed (-5)

    Regards
        Oliver

Re: UCSI failing due to probe() getting version 0

[Heikki Krogerus]

On Wed, Aug 11, 2021 at 04:47:13PM +0200, Oliver Neukum wrote:
> 
> On 11.08.21 15:23, Heikki Krogerus wrote:
> Hi,
> > Because of BIOS bugs.
> >
> > Ideally we should be able to rely on the _STA method of the ACPI
> > device, but unfortunately with UCSI we can't rely on that alone. On
> > some systems the BIOS claims that the device is enabled (based on
> > _STA) even when the platform doesn't actually support UCSI at all.
> >
> > If you remove the check, does the driver work?
> 
> Unfortunately, no it does not:

OK, so your laptop does not support UCSI even though the BIOS claims
it does.

thanks,

-- 
heikki