Date: Mon, 15 Aug 2005 18:08:32 -0700 From: Nate Lawson <nate@root.org> To: Hajimu UMEMOTO <ume@freebsd.org> Cc: acpi@freebsd.org Subject: Re: Annoyances with passive thermal code (acpi_thermal) Message-ID: <43013C90.7040901@root.org> In-Reply-To: <ygeacjj81bw.wl%ume@mahoroba.org> References: <20050814023842.C0D845D07@ptavv.es.net> <ygezmrk2van.wl%ume@mahoroba.org> <ygeoe7zacqg.wl%ume@mahoroba.org> <4300C5DF.40409@root.org> <ygek6in5e4t.wl%ume@mahoroba.org> <ygeacjj81bw.wl%ume@mahoroba.org>
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Hajimu UMEMOTO wrote:
> I found the cause. The saved_level is not stackable. So, an initial
> cpu level was saved, then a cpu level at CPUFREQ_PRIO_USER was not
> saved. Here is a patch to solve this problem:
>
> Index: sys/kern/kern_cpu.c
> diff -u -p sys/kern/kern_cpu.c.orig sys/kern/kern_cpu.c
> --- sys/kern/kern_cpu.c.orig Mon Apr 11 04:11:23 2005
> +++ sys/kern/kern_cpu.c Tue Aug 16 03:31:55 2005
> @@ -336,6 +336,7 @@ cf_set_method(device_t dev, const struct
> */
> if (sc->curr_level.total_set.freq != CPUFREQ_VAL_UNKNOWN &&
> sc->saved_level.total_set.freq == CPUFREQ_VAL_UNKNOWN &&
> + sc->curr_priority > CPUFREQ_PRIO_LOWEST &&
> priority > sc->curr_priority) {
> CF_DEBUG("saving level, freq %d prio %d\n",
> sc->curr_level.total_set.freq, sc->curr_priority);
>
> I think it is enough to solve CPUFREQ_PRIO_USER v.s. CPUFREQ_PRIO_KERN
> issue. However, it may better to have saved_level at each priority,
> IMHO.
The original intention was that we would save a stack of values and that
a CPUFREQ_SET(NULL, prio) would restore the last setting for the
priority before "prio".
Example:
freq = 1000 Mhz
CPUFREQ_SET(1200, PRIO_USER) -- saves 1000 Mhz @PRIO_LOWEST
freq = 1200
CPUFREQ_SET(1800, PRIO_LOWEST) -- EPERM since prio too low
freq = 1200
CPUFREQ_SET(1700, PRIO_KERN) -- saves 1200 Mhz @PRIO_USER
freq = 1700
CPUFREQ_SET(1900, PRIO_KERN) -- no saves since prio same as before
freq = 1900
CPUFREQ_SET(NULL, PRIO_KERN) -- restores 1200 Mhz @PRIO_USER
freq = 1200
CPUFREQ_SET(NULL, PRIO_USER) -- restores 1000 Mhz @PRIO_LOWEST
freq = 1000
Implementing this as a simple array would make sense. Would you be
willing to do this? If not, your patch should be fine for now.
--
Nate
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