Re: [PATCH] platform/chrome: cros_kbd_led_backlight: support Google Link

[Brandon Casey <drafnel@gmail.com>]

On November 13, 2024 8:07:42 PM CST, Tzung-Bi Shih <tzungbi@kernel.org> wrote:
>On Wed, Nov 13, 2024 at 02:44:55AM -0600, Brandon Casey wrote:
>> 
>> 
>> On November 13, 2024 12:46:18 AM CST, Tzung-Bi Shih <tzungbi@kernel.org> wrote:
>> >On Tue, Nov 12, 2024 at 08:29:05PM -0600, Brandon Casey wrote:
>> >> On the Google Pixel chromebook (aka Google Link), the keyboard led
>> >> backlight has the ACPI device id "GGL0002".  Let's add it to the
>> >> configuration array.
>> >
>> >Why it can't be matched by "GOOG0002"? [1] 
>> 
>> I'm not sure I understand this question. On my device the backlight has ACPI id "GGL0002", not "GOOG0002"?
>> 
>> >Have you tried to update your AP firmware?
>> 
>> I have not explicitly updated any firmware. It has whatever firmware Chromeos has installed.
>
>IIUC, if your AP firmware includes patch [1] (submitted in 2015), it should
>report "GOOG0002" instead of "GGL0002".
>
>[1]: https://review.coreboot.org/c/coreboot/+/11478

I can only assume that Google did not ever ship a firmware update for Link that included that patch. I believe this device has all ChromeOS updates applied, so it represents a stock system, though no longer supported, and aside from being in developer mode and having a Linux partition.

My firmware also reports the acpi device as GGL0001.

    $ cat /sys/bus/acpi/devices/GGL000*/hid
    GGL0001
    GGL0002

    $ cat /sys/bus/acpi/devices/GGL000*/path
    \CRHW
    \_SB_.KBLT

Is there any reason why we shouldn't do the same thing here for the keyboard backlight that was done in drivers/platform/chrome/chromeos_acpi.c and support both the legacy ID and the official ACPI ID? I see your commit 703e77134 which added GOOG0016 in addition to GGL0001.

-Brandon