Re: [External] [PATCH 1/2] platform/x86: thinkpad_acpi: Restore X1 Carbon 9th Gen dual fan quirk

[Mark Pearson <markpearson@lenovo.com>]

On 4/30/22 08:13, Thomas Weißschuh wrote:
> Hi Mark,
> 
> On 2022-04-29 21:25-0400, Mark Pearson wrote:
>> Hi Lyude
>>
>> On 4/29/22 17:14, Lyude Paul wrote:
>>> The new method of probing dual fan support introduced in:
>>>
>>> bf779aaf56ea ("platform/x86: thinkpad_acpi: Add dual fan probe")
>>>
>>> While this commit says this works on the X1 Carbon 9th Gen, it actually
>>> just results in hiding the second fan on my local machine. Additionally,
>>> I'm fairly sure this machine powers on quite often without either of the
>>> two fans spinning.
>>>
>>> So let's fix this by adding back the dual fan quirk for the X1 Carbon 9th
>>> Gen.
>>>
>> [..]
>>
>> I just double checked this on my X1C9 - and it's working correctly. 2nd
>> fan is detected correctly.
>>
>> I'd rather understand why it's not working on your setup then just
>> re-introduce the quirk.
>>
>> What happens on your system when the
>>   res = fan2_get_speed(&speed);
>> is called? If that is failing it means your 2nd fan isn't responding and
>> that's not supposed to happen. Could you let me know if you get an error
>> code, if it happens every boot, etc
>> I assume when the function is called later it works successfully?
> 
> I have the same issue.
> 
> To me it looks like this:
> 
> Probing for the second fan calls fan2_get_speed(), this calls
> fan_select_fan2() which in turn checks that tp_features.second_fan is set.
> But at this point in the tp_features.second_fan can not yet be set because it
> is either set from quirks or *after* the probing.
> 
> Maybe some of the matches for the quirk TPACPI_FAN_2FAN should also have
> matched this device?
> It doesn't do so on my device.
> 
>> Also please confirm which BIOS and EC version you have.
> 
> Linux: 5.17.5
> BIOS Revision: 1.51
> Firmware Revision: 1.32
> 
Thanks Thomas,
I'll go do some more digging on my system and see what I've missed.
Mark