[SOLVED] Where is CONFIG_APM in kernel

Aquarius_Girl · 06-01-2012, 01:28 AM

From here: http://www.xenomai.org/documentation...ROUBLESHOOTING

Quote:

Q: Which CONFIG_* items are latency killers, and should be avoided ?
...
APM: The APM model assigns power management control to the BIOS, and BIOS code is never written with RT-latency in mind. If configured, APM routines are invoked with SMI priority, which breaks the rule that adeos-ipipe must be in charge of such things. DISABLE_SMI doesnt help here (more later).

The problem is that I am not able to find this APM thing anywhere.

See the screenshots below:

"ACPI (Advanced Configuration and Power Interface) Support" results in the following menu:

Code:

 --- ACPI (Advanced Configuration and Power Interface) Support[*]   Deprecated /proc/acpi files[*]   Deprecated power /proc/acpi directories
 <M>   ACPI 4.0 power meter
 < >   EC read/write access through /sys/kernel/debug/ec (NEW)[*]   Deprecated /proc/acpi/event support
<M>   AC Adapter
<M>   Battery
{M}   Button
{M}   Video
<M>   Fan[*]   Dock
<M>   Processor
< >   IPMI (NEW)
<M>   Processor Aggregator
<M>   Thermal Zone
-*-   NUMA support
()    Custom DSDT
Table file to include[*]   Debug Statements
[ ]   Additionally enable ACPI function tracing
<M>   PCI slot detection driver
{M}   Container and Module Devices (EXPERIMENTAL)
<M>   Memory Hotplug
<M>   Smart Battery System
< >   Hardware Error Device (NEW)
[ ]   ACPI Platform Error Interface (APEI) (NEW)

Please help.

Didier Spaier · 06-01-2012, 02:14 AM

Hello Anisha,

just scroll down in "/" APM results using the "down" arrow key and at the end you'll find that (hopefully):

Code:

Symbol: APM [=n]                                                                                                            │  
  │ Type  : tristate                                                                                                            │  
  │ Prompt: APM (Advanced Power Management) BIOS support                                                                        │  
  │   Defined at arch/x86/Kconfig:1727                                                                                          │  
  │   Depends on: X86_32 [=y] && PM_SLEEP [=y]                                                                                  │  
  │   Location:                                                                                                                 │  
  │     -> Power management and ACPI options

Cheers,

Aquarius_Girl · 06-01-2012, 03:26 AM

Sorry, but I couldn't get your point here.
I can't see APM in "Power management and ACPI options".
Did you see the second screenshot?
What's the point that I am missing?

Thanks for your time , BTW.

EDIT
Actually, I am using "make menuconfig". That shows a GUI. This option isn't there in "Power management and ACPI support". I did attach the screenshot. what am I over looking? –

Didier Spaier · 06-01-2012, 05:58 AM

I did notice that you are using "make menuconfig". So do I

Please post the results of following commands:

Code:

grep X86_32 .config
grep PM_SLEEP .config

or append your .config to next post.

My guess is that you don't have "CONFIG_X86_32=y" and "CONFIG_PM_SLEEP=y".

Bear in mind that "make menuconfig" only displays a menu entry if its dependencies are met.

Aquarius_Girl · 06-01-2012, 06:30 AM

Thankful for your patience.

Code:

linux-y3pi:/usr/src/linux-2.6.38.8 # grep X86_32 .config
# CONFIG_X86_32 is not set

linux-y3pi:/usr/src/linux-2.6.38.8 # grep PM_SLEEP .config
CONFIG_PM_SLEEP_SMP=y
CONFIG_PM_SLEEP=y
# CONFIG_PM_SLEEP_ADVANCED_DEBUG is not set

So, now I opened the .config and set CONFIG_X86_32 to y and saved.
Still, APM isn't visible through make menuconfig.

Well, learning comes at a cost.

Didier Spaier · 06-01-2012, 07:25 AM

I did "make menuconfig" with your .config and APM is visible.

Thus I don't understand why it is not for you

EDIT

Quote:

Originally Posted by Anisha Kaul

So, now I opened the .config and set CONFIG_X86_32 to y and saved.

If you mean that you did use an editor for that I'm not sure it can work. Though I be not sure of that my guess is you should use "make menuconfig" to change a config setting.

Didier Spaier · 06-03-2012, 07:58 AM

The reason why we don't get the same results is that APM depends on X86_32 [=y].

But this dependency can be met only if CONFIG_X86_32 is defined, which is done in the "make *config" process only for relevant ARCHs.

Unless explicitly stated by the user the ARCH variable's value is set up according to the results of the "uname -m" command in the main Makefile of the kernel source tree, in our case linux-2.6.38/Makefile:

Code:

# SUBARCH tells the usermode build what the underlying arch is.  That is set
# first, and if a usermode build is happening, the "ARCH=um" on the command
# line overrides the setting of ARCH below.  If a native build is happening,
# then ARCH is assigned, getting whatever value it gets normally, and
# SUBARCH is subsequently ignored.

SUBARCH := $(shell uname -m | sed -e s/i.86/i386/ -e s/sun4u/sparc64/ \
                                 -e s/arm.*/arm/ -e s/sa110/arm/ \
                                 -e s/s390x/s390/ -e s/parisc64/parisc/ \
                                 -e s/ppc.*/powerpc/ -e s/mips.*/mips/ \
                                 -e s/sh[234].*/sh/ )

# Cross compiling and selecting different set of gcc/bin-utils
#
---------------------------------------------------------------------------
#
# When performing cross compilation for other architectures ARCH shall be
set
# to the target architecture. (See arch/* for the possibilities).
# ARCH can be set during invocation of make:
# make ARCH=ia64
# Another way is to have ARCH set in the environment.
# The default ARCH is the host where make is executed.

This is confirmed in linux-2.6.38/Documentation/kbuild/makefiles.txt:

Code:

   ARCH

       This variable defines the target architecture, such as "i386",
       "arm", or "sparc". Some kbuild Makefiles test $(ARCH) to
       determine which files to compile.

       By default, the top Makefile sets $(ARCH) to be the same as the
       host system architecture.  For a cross build, a user may
       override the value of $(ARCH) on the command line:

           make ARCH=m68k ...

Here "uname -m" result is "i686" thus CONFIG_APM is defined in the "make menuconfig" process.

But if I type for instance "make ARCH=arm menuconfig" neither CONFIG_X86_32 nor CONFIG_APM are defined thus there is no menu entry for APM in the "menuconfig" screens.

Aquarius_Girl · 06-03-2012, 09:35 AM

The spread system doesn't allow me to click the scales icon.
I am grateful for all your offline and online assistance.