From: Kevin Hilman <khilman@ti.com>
To: javier Martin <javier.martin@vista-silicon.com>
Cc: linux-omap@vger.kernel.org, Koen Kooi <koen@beagleboard.org>
Subject: Re: cpuidle status in mainline for Beagleboard xM
Date: Thu, 01 Sep 2011 08:10:15 -0700 [thread overview]
Message-ID: <87vctcjo2w.fsf@ti.com> (raw)
In-Reply-To: <CACKLOr10aTCwkBZnSinvP4HLPhrJeiBs=6KM2we4DwTT0NJ22A@mail.gmail.com> (javier Martin's message of "Thu, 1 Sep 2011 16:14:00 +0200")
javier Martin <javier.martin@vista-silicon.com> writes:
> I am trying to enable cpuidle and cpufreq support in latest stable
> kernel (3.0.4) in the Beagleboard xM.
OMAP CPUfreq driver is still not in mailine. I plan to rectify that
(finally) for v3.2. In the mean time, feel free to try the
pm-wip/cpufreq branch from my linux-omap-pm tree[1] (currently based on
v3.0-rc3)
> The default governor I've selected in the kernel menu is "powersave".
> However, when I execute powertop 1.12 (downloaded from Angstrom 2010.x
> repository through opkg) I get the following:
>
>
> Cn Avg residency P-states (frequencies)
> C0 (cpu running) ( 0.4%)
> C0 16.7ms (99.6%)
> C1 0.0ms ( 0.0%)
> C2 0.0ms ( 0.0%)
> C3 0.0ms ( 0.0%)
> C4 0.0ms ( 0.0%)
> C5 0.0ms ( 0.0%)
> C6 0.0ms ( 0.0%)
>
> So, the CPU always stays in C0 status and P-states are not shown.
P-states are not shown because there is no CPUfreq driver, so no
P-states available, and of course the choice of CPUfreq governor doesn't
matter.
CPU is staying in C0 probably because UARTs are not being idled, so SoC
cannot hit deeper idle states. Try the following at the command line to
to enable UART idle timeouts, so the SoC can attempt idle after the
timeout period
# UART timeouts: omap-serial (4th UART only on OMAP36xx and OMAP4)
echo 5 > /sys/devices/platform/omap/omap_uart.0/sleep_timeout
echo 5 > /sys/devices/platform/omap/omap_uart.1/sleep_timeout
echo 5 > /sys/devices/platform/omap/omap_uart.2/sleep_timeout
echo 5 > /sys/devices/platform/omap/omap_uart.3/sleep_timeout
After 5 seconds of inactivity on the UARTs, you should see the SoC
hitting deeper C-states.
Kevin
[1] git://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-omap-pm.git
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next prev parent reply other threads:[~2011-09-01 15:10 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-01 14:14 cpuidle status in mainline for Beagleboard xM javier Martin
2011-09-01 15:10 ` Kevin Hilman [this message]
2011-09-01 15:33 ` javier Martin
2011-09-01 17:46 ` Kevin Hilman
2011-09-02 6:05 ` Jarkko Nikula
2011-09-02 7:23 ` javier Martin
2011-09-02 17:14 ` Kevin Hilman
2011-09-05 8:04 ` javier Martin
2011-09-06 21:04 ` Kevin Hilman
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