Nailing the Cause of Recent Linux Power Issues 156
Posted
by
timothy
from the building-a-better-eyeball dept.
from the building-a-better-eyeball dept.
An anonymous reader writes "For the Linux kernel power regressions that were found a few months ago, and hit in Ubuntu 11.04, Phoronix has found the regression that's still present in the Linux 3.0 kernel. The power regression is caused by a change in ASPM, the Active-State Power Management, for PCI Express support."
Summary: not a Linux problem, but a BIOS problem (Score:5, Informative)
It's due to some buggy BIOSes not properly advertising power-saving features of PCIE cards. Older kernels didn't honor those BIOS hints, and disabled power to unused PCIE cards anyways (causing hangs in rare cases), whereas new kernels do the right thing (causing power wastage in lots of cases). The workaround is to specify pcie_aspm=force on the boot (Grub) command line, to tell the kernel to forge ahead, and just use power management on these cards regardless of the BIOS advice.
Re:No more Moronix, please! (Score:5, Informative)
tl;dr (Score:3, Informative)
Test it by editing grub (which is a temporary edit that will be lost next boot) first and test out suspend, hibernate, etc.
If that works, edit your grub configuration files. For ubuntu users this means editing
Re:Summary: not a Linux problem, but a BIOS proble (Score:4, Informative)
The article points out that there is also a power regression in the scheduler. Which is the next thing that the writer will look at.
Never upgrade your Linux... (Score:2, Informative)
Never upgrade your Linux distribution in place.
Have 2 (or more) OS partitions of about 20GB each.
Install your OS's to partition 1.
Install your upgraded version to partition 2.
Easily switch back and forth.
Oh, and keep a separate /home partition.
Re:"serious bug" my ass (Score:5, Informative)
You are entirely correct. See Matthew Garrett's blog [dreamwidth.org] for the icky details of EFI on Linux. He makes this hideous piece of shit work for a living.
Re:Summary: not a Linux problem, but a BIOS proble (Score:4, Informative)
Re:ACPI has ALWAYS favoured Windows... (Score:5, Informative)
ACPI implementors (what is an ACPI vendor? can I buy it by the pound, or is it sold by the unit?) favored Windows, because Microsoft built a tool for creating ACPI tables that intentionally craps on all other operating systems, INTENTIONALLY building an invalid table for use with non-Windows operating systems. Linux now claims to be Windows in order to get a table that works. Bill Gates proposed this "feature" personally.
The dominant platform is the one supported by fraud and deceit, which helps to ensure its continuing dominance, and the proper use of apostrophes. No wait, that was me.
Re:Summary: not a Linux problem, but a BIOS proble (Score:5, Informative)
Did you read the linked PDF at all? Here's what the rest of it said:
In summary, Bill Gates explicitly wanted to break ACPI on Linux.