Re: programs using the /proc interface are broken.

[Sven Joachim <svenjoac@gmx.de>]

On 2008-08-19 10:39 +0200, Chris Bannister wrote:

> Hi,
>
> It looks like any programs using the /proc interface are now broken, at
> least with the later kernels.

No, only those that read /proc/acpi/battery.  That directory does not
exist in current Debian kernels because of the reckless decision to
build them without CONFIG_ACPI_PROCFS_POWER.  Hopefully the Debian
kernel team will revert this before Lenny.

> root@box:~# uname -a
> Linux box 2.6.25-2-686 #1 SMP Fri Jul 18 17:46:56 UTC 2008 i686 GNU/Linux
>
> Compare:
>
> root@box:~# acpi -b
>      Battery 0: Charging, 100%,  until charged [1]
>
> with:
> root@box:~# acpi -p -b
> No support for device type: battery
>
> root@box:~# man acpi
> [..]
>        -p | --proc
>                  use the old /proc interface, default is the new /sys one
>
> I have noticed this behaviour with at least two packages so far:
> laptop-detect, and fvwm-crystal.

And xbattbar-acpi[0], yacpi[1], icewm[2], acpi-support[3], emacs[4],
and, and, and,...

> [1] Doesn't seem like the /sys interface is any easier to parse. :-(

Quoting Documentation/sysfs-rules.txt in Linux 2.6.26:

,----
| The kernel-exported sysfs exports internal kernel implementation details
| and depends on internal kernel structures and layout. It is agreed upon
| by the kernel developers that the Linux kernel does not provide a stable
| internal API. As sysfs is a direct export of kernel internal
| structures, the sysfs interface cannot provide a stable interface either;
| it may always change along with internal kernel changes.
`----

Go figure. :-(

Sven


0. http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=479096
1. http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=484264
2. http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=492403
3. http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=491396
4. http://emacsbugs.donarmstrong.com/cgi-bin/bugreport.cgi?bug=660