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. > > Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx> > Fixes: bf779aaf56ea ("platform/x86: thinkpad_acpi: Add dual fan probe") > Cc: Mark Pearson <markpearson@xxxxxxxxxx> > Cc: Hans de Goede <hdegoede@xxxxxxxxxx> > Cc: Henrique de Moraes Holschuh <hmh@xxxxxxxxxx> > Cc: Mark Gross <markgross@xxxxxxxxxx> > Cc: ibm-acpi-devel@xxxxxxxxxxxxxxxxxxxxx > Cc: platform-driver-x86@xxxxxxxxxxxxxxx > --- > drivers/platform/x86/thinkpad_acpi.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c > index c568fae56db2..9067fd0a945c 100644 > --- a/drivers/platform/x86/thinkpad_acpi.c > +++ b/drivers/platform/x86/thinkpad_acpi.c > @@ -8699,6 +8699,7 @@ static const struct tpacpi_quirk fan_quirk_table[] __initconst = { > TPACPI_Q_LNV3('N', '2', 'E', TPACPI_FAN_2CTL), /* P1 / X1 Extreme (1st gen) */ > TPACPI_Q_LNV3('N', '2', 'O', TPACPI_FAN_2CTL), /* P1 / X1 Extreme (2nd gen) */ > TPACPI_Q_LNV3('N', '3', '0', TPACPI_FAN_2CTL), /* P15 (1st gen) / P15v (1st gen) */ > + TPACPI_Q_LNV3('N', '3', '2', TPACPI_FAN_2CTL), /* X1 Carbon (9th gen) */ > TPACPI_Q_LNV3('N', '3', '7', TPACPI_FAN_2CTL), /* T15g (2nd gen) */ > TPACPI_Q_LNV3('N', '1', 'O', TPACPI_FAN_NOFAN), /* X1 Tablet (2nd 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? Also please confirm which BIOS and EC version you have. Thanks Mark