linux-kernel - Re: [PATCH] ACPI: scan: Ignore MAGN0001

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Message-ID: <d0068345-6832-c9ae-ec40-bb692baa3f69@mariushoch.de>
Date:   Sat, 22 Apr 2023 18:47:35 +0200
From:   Marius Hoch <mail@...iushoch.de>
To:     Hans de Goede <hdegoede@...hat.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Len Brown <lenb@...nel.org>, linux-acpi@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ACPI: scan: Ignore MAGN0001

Hi Hans,

On 21/04/2023 20:07, Hans de Goede wrote:
> Hi Marius,
>
> On 4/21/23 18:27, Marius Hoch wrote:
>> The LSM303D on the Lenovo Yoga Tablet 2 series is present
>> as both ACCL0001 and MAGN0001. As we can only ever register an
>> i2c client for one of them, ignore MAGN0001.
>>
>> Currently this errors:
>> i2c i2c-4: Failed to register i2c client MAGN0001:00 at 0x1d (-16)
>>
>> Tested on a Lenovo Yoga Tablet 2 1051-F.
>>
>> Signed-off-by: Marius Hoch <mail@...iushoch.de>
> By adding the HID to the ignore_serial_bus_ids[] list, you are
> causing the ACPI code to instead instantiate a platform_device
> for it.
>
> This will successfully silence the error you are trying to silence,
> but I don't think it really is what you intent / want to do ?
It is not, no. Given we will only ever care for ACCL0001, we can 
entirely skip MAGN0001.
>
> IMHO it would be better to add a NOT_PRESENT_ENTRY_HID() entry
> to the override_status_ids[] table in drivers/acpi/x86/utils.c,
> this will override the return of _STA, causing neither a
> platform_device not an i2c_client to get instantiated for
> the duplicate MAGN0001 device.
That sounds much better, thanks for the pointer!
I've send a new patch (20230422164401.5986-1-mail@...iushoch.de).

Cheers,
Marius
>
> (please keep the comment above the entry why the entry is there)
>
> Regards,
>
> Hans
>
>
>
>
>
>
>
>> ---
>>   drivers/acpi/scan.c | 6 ++++++
>>   1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
>> index 0c6f06abe3f4..d21c411e9719 100644
>> --- a/drivers/acpi/scan.c
>> +++ b/drivers/acpi/scan.c
>> @@ -1730,6 +1730,12 @@ static bool acpi_device_enumeration_by_parent(struct acpi_device *device)
>>   	 */
>>   		{"BCM4752", },
>>   		{"LNV4752", },
>> +	/*
>> +	 * The LSM303D on the Lenovo Yoga Tablet 2 series is present
>> +	 * as both ACCL0001 and MAGN0001. As we can only ever register an
>> +	 * i2c client for one of them, ignore MAGN0001.
>> +	 */
>> +		{"MAGN0001", },
>>   		{}
>>   	};
>>   
>>
>> base-commit: cb0856346a60fe3eb837ba5e73588a41f81ac05f