Bug 601195 - ahci power saving change may result in failure to identify disks
Summary: ahci power saving change may result in failure to identify disks
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: kernel
Version: 6.0
Hardware: All
OS: Linux
Target Milestone: rc
: ---
Assignee: John Feeney
QA Contact: Red Hat Kernel QE team
Depends On:
TreeView+ depends on / blocked
Reported: 2010-06-07 12:57 UTC by Matthew Garrett
Modified: 2013-01-10 07:50 UTC (History)
2 users (show)

Clone Of:
Last Closed: 2010-11-11 16:13:56 UTC

Attachments (Terms of Use)
Patch to fix this (2.16 KB, patch)
2010-06-07 13:02 UTC, Matthew Garrett
no flags Details | Diff

Description Matthew Garrett 2010-06-07 12:57:17 UTC
Bugzilla 577967 added code for powering down ahci DMA engines if there's no device attached. This appears to occasionally result in a failure to identify devices and a consequent failure to boot.

Comment 1 Matthew Garrett 2010-06-07 13:02:26 UTC
Created attachment 421812 [details]
Patch to fix this

Comment 3 RHEL Product and Program Management 2010-06-07 13:33:14 UTC
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux major release.  Product Management has requested further
review of this request by Red Hat Engineering, for potential inclusion in a Red
Hat Enterprise Linux Major release.  This request is not yet committed for

Comment 4 Matthew Garrett 2010-06-09 20:36:57 UTC
Posted on June 9th.

Comment 6 Aristeu Rozanski 2010-07-01 16:22:30 UTC
Patch(es) available on kernel-2.6.32-42.el6

Comment 9 Mike Gahagan 2010-09-02 17:27:34 UTC
We've booted numerous snapshots since Beta on AHCI systems. Additionally setting of link power has not affected subsequent boots or devices already attached on any of the systems I've tested AHCI link power management on. 

Hotplugged devices are the exception where link power management has to be set to max_performance in order for device detection to work. The kernel should disallow this on any hotpluggable SATA port already.

Comment 10 releng-rhel@redhat.com 2010-11-11 16:13:56 UTC
Red Hat Enterprise Linux 6.0 is now available and should resolve
the problem described in this bug report. This report is therefore being closed
with a resolution of CURRENTRELEASE. You may reopen this bug report if the
solution does not work for you.

Note You need to log in before you can comment on or make changes to this bug.