Red Hat Bugzilla – Bug 475502
[LTC 5.4 FEAT] ACPI C3/C4 Support 
Last modified: 2011-02-22 04:41:58 EST
Emily J. Ratliff <email@example.com> -
1. Feature Overview:
Feature Id: 
a. Name of Feature: ACPI C3/C4 Support
b. Feature Description
Power savings is quickly becoming one of the main focus areas for system x. We need to ensure
additional ACPI power states (c-states), particularly c3/c4 deep sleep modes, are supported in Linux
so they are ready to be used at the enterprise level, and in support of IBM's power management strategy.
Additional Comments: Once we get C3/C4 enabled hardware we will be validating this feature in 5.4.
One bug fix that we are looking for is bugzilla 474091 (TSC keeps running in C3+).
2. Feature Details:
Arch Specificity: Both
Affects Core Kernel: Yes
Affects Kernel Modules: Yes
Delivery Mechanism: Direct from community
Request Type: Kernel - Enhancement from IBM
d. Upstream Acceptance: Accepted
Sponsor Priority 1
f. Severity: High
IBM Confidential: no
Code Contribution: no
g. Component Version Target: Some of this may just work, because laptops already support this. For
Servers, it must be tested. However, until we have servers that support C3/C4, it's difficult to
guess which upstream kernel any code (if needed) will be targeted for.
3. Business Case
IBM Active Energy Manager will require ACPI C3/C4 Support
4. Primary contact at Red Hat:
5. Primary contacts at Partner:
Project Management Contact:
Monte Knutson, firstname.lastname@example.org, 877-894-1495
Kevin Stansell, email@example.com
Chris McDermott, firstname.lastname@example.org
Julio Alvarez, email@example.com
IBM is signed up to test and provide feedback.
What is the status of the C3/C4 enabled hardware? Has this been tested with the latest 5.3 code?
We have verified C3/C4 support on an iDataPlex dx340. We now have C3/C4 enabled on x3550 M2 and x3650 M2. We will confirm RHEL5.3 works correctly on those platforms and report the results here. If all goes well this can be closed.
Updating PM score.
Any update on the testing mentioned in this bug? Did this work correctly with RHEL 5.3?
------- Comment From firstname.lastname@example.org 2009-03-25 19:51 EDT-------
Seems to work fine with the RHEL 5.3 RC2 kernel (2.6.18-128.el5), thanks. :)
Closing CURRENTRELEASE based on comment 6
------- Comment From 2011-02-22 04:38 EDT-------
We are reviewing this as a part of backlog bug clean up activity.
Please feel free to reopen once you have any valid update.
------- Comment From 2011-02-22 04:40 EDT-------
(In reply to comment #12)
> We are reviewing this as a part of backlog bug clean up activity.
> Please feel free to reopen once you have any valid update.
Closed this bug as per Redhat's comment.