Hello, I have gentoo hardened system with /sys restrictions and xfce4-battery-plugin fails to find battery.
Problem is caused by following lines from xfce4-battery-plugin/tree/panel-plugin/libacpi.c (lines 289 - 297)

  if (!(acpi = fopen ("/proc/acpi/info", "r"))
      && !(acpi = fopen ("/sys/module/acpi/parameters/acpica_version", "r")))
  {
#ifdef DEBUG
	  printf("DBG:no acpi: /proc/acpi/info or "
             "/sys/module/acpi/parameters/acpica_version not found!\n");
#endif
    return 1;
  }

I have no /proc/acpi/info file (quick googling suggests it was deprecated) and /sys access is restricted due to grsecurity kernel patchset. However after removing them plugin seems to work without problems (getting it's info from /proc/acpi/battery/BAT1/info).

Now my question is: is this check really necessary or can it be removed upstream?