Bug 5021

Summary:	Safely change pm_idle
Product:	ACPI	Reporter:	Shaohua (shaohua.li)
Component:	Power-Processor	Assignee:	Len Brown (lenb)
Status:	REJECTED INVALID
Severity:	normal	CC:	acpi-bugzilla
Priority:	P2
Hardware:	i386
OS:	Linux
Kernel Version:	2.6.13-rc5	Subsystem:
Regression:	---	Bisected commit-id:
Attachments:	patch to use cpu_idle_wait patch to use cpu_idle_wait updated patch updated patch

Description Shaohua 2005-08-07 23:16:23 UTC

synchronize_sched() only guarantees all CPUs have exited non-preemptive block. 
From my understanding, we want the affected CPU exits idle (in 
acpi_processor_cst_has_changed), so synchronize_sched() doesn

Comment 1 Shaohua 2005-08-07 23:19:11 UTC

Created attachment 5542 [details]
patch to use cpu_idle_wait

The patch does:
It does:
1. change pm idle fix. 
2. cleanup for acpi_processor_get_power_info_cst to make it use less stack
space (acpi_processor_cx is a big structure)

Comment 2 Shaohua 2005-08-07 23:19:20 UTC

Created attachment 5543 [details]
patch to use cpu_idle_wait

The patch does:
It does:
1. change pm idle fix. 
2. cleanup for acpi_processor_get_power_info_cst to make it use less stack
space (acpi_processor_cx is a big structure)

Comment 3 Len Brown 2005-09-02 23:04:38 UTC

patch needs to be re-based on Lindented processor_idle.c

Comment 4 Shaohua 2005-09-07 00:10:20 UTC

Created attachment 5921 [details]
updated patch

A updated patch. It tries to fix all races.

Comment 5 Shaohua 2005-09-14 00:09:31 UTC

Created attachment 6005 [details]
updated patch

My last patch still has a small race window when one CPU is reading per-cpu
idle and another CPU is changing it. This updated one fixes it.

Comment 6 Len Brown 2007-03-08 21:24:39 UTC

patch does not apply to current tree -- re-opening

Comment 7 Shaohua 2007-03-08 23:01:54 UTC

with cpuidle, this patch isn't required.