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PCIe, power management, and problematic BIOSes

PCIe, power management, and problematic BIOSes

Posted Jun 30, 2011 17:08 UTC (Thu) by iceblink (subscriber, #19982)
In reply to: PCIe, power management, and problematic BIOSes by flewellyn
Parent article: PCIe, power management, and problematic BIOSes

In at least one BIOS that I have worked with the ACPI spec was simply mis-interpreted as needing this flag to be set it to 1 in order to enable ASPM. Seems like a silly mistake but I suspect it is common.

The kernel should probably also be checking to see if the FACS claims to support ACPI 4.0 before relying on this flag.


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PCIe, power management, and problematic BIOSes

Posted Jun 30, 2011 17:24 UTC (Thu) by mjg59 (subscriber, #23239) [Link]

Did anyone test that ASPM actually ended up enabled as a result? You're right that the check should be made conditional on the FADT version, though.

PCIe, power management, and problematic BIOSes

Posted Jul 2, 2011 2:05 UTC (Sat) by iceblink (subscriber, #19982) [Link]

Yeah we noticed a spike in power testing and ended up with a DMI workaround until BIOS updates can be rolled out: http://crosbug.com/15124

PCIe, power management, and problematic BIOSes

Posted Jul 2, 2011 3:05 UTC (Sat) by mjg59 (subscriber, #23239) [Link]

Ah, ok, I hadn't realised this was Chrome OS. My concern is more that BIOS vendors in general have this opinion, and Windows handles it differently to us in some way.


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