# [SOLVED] ACPI Warning: If an ACPI driver is available ...

## charles17

 *dmesg wrote:*   

> 
> 
> [    0.888556] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
> 
> [    0.888580] [drm] Driver supports precise vblank timestamp query.
> ...

 

What do these ACPI Warnings try to tell me? 

 *Quote:*   

> If an ACPI driver is available for this device

 

Which device does it mean?Last edited by charles17 on Tue Sep 05, 2017 7:31 am; edited 1 time in total

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## eccerr0r

I've only run across this when I try using a "native" lm_sensors driver.  The problem being that ACPI already is using the device and thus there's a conflict (can't have two pieces of software directly accessing a device) and since there's no way to lock to mutex the two drivers, unfortunately, it means ACPI wins and a hope that there's an ACPI driver to get the data from that resource that was conflicting.

However it looks like a lot of people are seeing this new issue, including myself, with the new kernels (4.9.34+ ?).  It looks like the conflicting driver is lpc_ich conflicting with ACPI.

At least for me I think I'm going to ignore the warning.  It's been working for all this time well before they decided to put this warning in, so I'm not going to sweat it for now...

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## charles17

Thanks eccerr0r,

If I had read more carefully, I should have seen that other line saying

```
[ 1.086257] lpc_ich: Resource conflict(s) found affecting gpio_ich 
```

Does this altogether mean I should use Intel ICH GPIO ( CONFIG_GPIO_ICH ) in addition to Intel ICH LPC ( CONFIG_LPC_ICH ) or instead of it?

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## Yamakuzure

The question is, whether you actually use your GPIO pins on your hardware. If not, you just use LPC instead of GPIO.

I am asking, because GPIO pins are normally unused but on SoC devices (Like the Raspberry Pi). Some Laptop manufacturers use them for some additional functionality in certain devices, but those are handled by the device drivers.

If you want to read more about GPIO, the kernel docs on GPIO might be of some interest.

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## charles17

Thanks Yamakuzure for the link.  In fact on this laptop, GPIO is not set at all.

Those messages in dmesg (see OP) are really confusing for me.

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