Re: Regression: Linux 2.6.31-rc7 lost sensors on asus mobo

From: Stefan Richter
Date: Sat Aug 22 2009 - 06:58:30 EST


Robert Hancock wrote:
On 08/21/2009 09:09 PM, Gene Heskett wrote:
From messages when I attempt to access the it87:
Aug 21 22:59:37 coyote kernel: [ 572.507928] it87: Found IT8716F chip at 0x290, revision 1
Aug 21 22:59:37 coyote kernel: [ 572.507937] it87: in3 is VCC (+5V)
Aug 21 22:59:37 coyote kernel: [ 572.507939] it87: in7 is VCCH (+5V Stand-By)
Aug 21 22:59:37 coyote kernel: [ 572.508232] ACPI: I/O resource it87 [0x295-0x296] conflicts with ACPI region IP__ [0x295-0x296]
Aug 21 22:59:37 coyote kernel: [ 572.508234] ACPI: Device needs an ACPI driver
...
The ACPI AML on your machine indicates that the BIOS may attempt to access the it87 hardware, and the kernel now by default blocks it87 from requesting those ports as it may conflict with what the BIOS is trying to do. On some machines, the ACPI BIOS accesses hardware monitoring chips itself to manage ACPI thermal zones, etc. and the conflicting access can cause incorrect temperature readings and other bad behavior.

You can try acpi_enforce_resources=lax on the kernel command line to restore the previous behavior. Or for some Asus boards, you can try the asus_atk0110 ACPI driver instead of it87.

PS: There have been previous reports, e.g. those logged as http://bugzilla.kernel.org/show_bug.cgi?id=13967
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Stefan Richter
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http://arcgraph.de/sr/
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