linux-kernel - Re: APM_CONFIG on x86

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Date:	Fri, 31 Dec 2010 23:40:10 +0200
From:	Yotam Medini <yotam.medini@...il.com>
To:	Randy Dunlap <rdunlap@...otime.net>
Cc:	linux-kernel@...r.kernel.org, Avery Pennarun <apenwarr@...mnit.ca>
Subject: Re: APM_CONFIG on x86 - Is it possible?

The .config I ended up with does have:
   CONFIG_APM=m
But no CONFIG_APM_POWER setting, 
When booting the kernel, I don not have /proc/apm.
I do get:

  $ sudo modprobe apm
  FATAL: Error inserting apm 
    (/lib/modules/2.6.32.yumax/kernel/arch/x86/kernel/apm.ko): No such device

Please note that 
  drivers/power/Makefile:118
has:
  obj-$(CONFIG_APM_POWER) += apm_power.o

Also the "/proc/apm" is created in 
  drivers/char/Makefile:71
    obj-$(CONFIG_APM_EMULATION)	+= apm-emulation.o
  drivers/char/apm-emulation.c:668-670
    #ifdef CONFIG_PROC_FS
	    proc_create("apm", 0, NULL, &apm_proc_fops);
    #endif
As far as I understand, CONFIG_APM is not sufficient 
for the creation of "/proc/apm".

-- yotam


On Fri, 31 Dec 2010 11:39:54 -0800
Randy Dunlap <rdunlap@...otime.net> wrote:

> On Fri, 31 Dec 2010 21:28:00 +0200 Yotam Medini wrote:
> 
> > Randy,
> > 
> > Thanks for your quick reply.
> > Sorry, but the subject line should have been:
> >   APM_POWER on x86 - Is it possible?  
> 
> Nope, not on X86.
> 
> > I do get 
> >   CONFIG_APM=m
> > in the .config, but I am trying to get 
> >   CONFIG_APM_POWER=m
> > as well. So far, I do not see how.  
> 
> APM_POWER depends on APM_EMULATION, which is not available on X86.
> But real APM is available on X86, so why would you need APM_EMULATION
> instead of APM_FOR_REAL ?
> 
> Enabling APM (according to its Kconfig help text) provides /proc/apm
> battery status information.
> 

On Fri, 31 Dec 2010 11:25:04 -0800
Avery Pennarun <apenwarr@...mnit.ca> wrote:

> On Fri, Dec 31, 2010 at 4:09 AM, Yotam Medini יותם מדיני
> <yotam.medini@...il.com> wrote:
> > For a target ancient UMAX-ActionBook 530T, I am trying to compile
> > a Linux kernel that will support apm (/proc/apm)
> > for battery monitoring.
> > Alas, it looks like that with current 2.6.3n.* kernels
> > it is not possible to configure CONFIG_APM_POWER on x86(/i386)
> > architectures.
> >
> > Am I missing something, is there a bypass?  
> 
> CONFIG_APM still exists and can be enabled in 2.6.36 for me.
> 
> Avery

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