From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
To: Oliver Neukum <oneukum@suse.com>
Cc: USB list <linux-usb@vger.kernel.org>
Subject: Re: UCSI failing due to probe() getting version 0
Date: Wed, 11 Aug 2021 16:23:26 +0300 [thread overview]
Message-ID: <YRPPTjaFLy5t5HsP@kuha.fi.intel.com> (raw)
In-Reply-To: <db9e63df-80cc-6dae-89ae-23cb1cd09425@suse.com>
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
next prev parent reply other threads:[~2021-08-11 13:23 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-05 14:04 UCSI failing due to probe() getting version 0 Oliver Neukum
2021-08-11 13:23 ` Heikki Krogerus [this message]
2021-08-11 14:47 ` Oliver Neukum
2021-08-12 8:10 ` Heikki Krogerus
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