kern/184757: Resume fails on the X200 when the C3 power mode is available and engaged
R Tyler Croy
tyler at monkeypox.org
Fri Dec 13 20:00:03 UTC 2013
>Number: 184757
>Category: kern
>Synopsis: Resume fails on the X200 when the C3 power mode is available and engaged
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Dec 13 20:00:02 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator: R Tyler Croy
>Release: FreeBSD 10.0-PRERELEASE amd64
>Organization:
>Environment:
FreeBSD kiwi 10.0-PRERELEASE FreeBSD 10.0-PRERELEASE #4 r259211: Wed Dec 11 01:08:00 PST 2013 root at kiwi:/usr/obj/usr/src/sys/KIWI amd64
>Description:
When tuning some of the performance and power settings, I tried enabling the C3 state as the "lowest" economy power setting.
This works all well and good, *unless* I suspend while on battery after some period of idle activity
/etc/rc.conf
----8<----8<----8<---
# Performance and power tuning taken from TuningPowerconsumption wiki
performance_cx_lowest="C2"
economy_cx_lowest="C3"
----8<----8<----8<---
/boot/loader.conf
----8<----8<----8<---
# Performance and power tuning taken from TuningPowerConsumption wiki
#####################################################################
# Disable PCI bus devices we don't have something built into the kernel
# for.
hw.pci.do_power_nodriver=3
# Disable throttling that would be hidden by the C2 state
hint.p4tcc.0.disabled=1
hint.acpi_throttle.0.disabled=1
# Enable clocks to make the C3 state viable
hint.apic.0.clock=0
hint.atrtc.0.clock=0
# Reduce the interrupt rate to make C3 more effective
kern.hz=100
----8<----8<----8<---
>How-To-Repeat:
* Enable the C3 state.
* Suspend while on battery, typically after some period of inactivity, allowing the machine to enter C3
* Attempt to resume
Observe the black screen on resume followed by a reboot a short time after that.
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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