bug#643: Battery update

[Chong Yidong]

Sven Joachim <svenjoac@gmx.de> writes:

>> What about (from the shell)
>>
>>   cat /sys/class/power_supply/BAT0/uevent
>
> POWER_SUPPLY_VOLTAGE_NOW=12444000
> POWER_SUPPLY_CURRENT_NOW=0
> POWER_SUPPLY_CHARGE_FULL_DESIGN=4000000
> POWER_SUPPLY_CHARGE_FULL=3985000
> POWER_SUPPLY_CHARGE_NOW=3985000
> POWER_SUPPLY_MODEL_NAME=GC86503SY90 
> POWER_SUPPLY_MANUFACTURER=SONY 
> POWER_SUPPLY_SERIAL_NUMBER=

Maybe it's a Lisp integer overflow (I'm guessing you're on a 32-bit
machine).  Does the following patch give better results?

*** trunk/lisp/battery.el.~1.46.~       2008-05-06 03:57:26.000000000 -0400
--- trunk/lisp/battery.el       2008-08-07 16:31:34.000000000 -0400
***************
*** 47,52 ****
--- 47,56 ----
        ((and (eq system-type 'gnu/linux)
              (file-directory-p "/proc/acpi/battery"))
         'battery-linux-proc-acpi)
+       ((and (eq system-type 'gnu/linux)
+             (file-directory-p "/sys/class/power_supply/")
+             (directory-files "/sys/class/power_supply/" nil "BAT[0-9]$"))
+        'battery-linux-sysfs)
        ((and (eq system-type 'darwin)
              (condition-case nil
                  (with-temp-buffer
***************
*** 70,75 ****
--- 74,81 ----
  (defcustom battery-echo-area-format
    (cond ((eq battery-status-function 'battery-linux-proc-acpi)
         "Power %L, battery %B at %r (%p%% load, remaining time %t)")
+       ((eq battery-status-function 'battery-linux-sysfs)
+        "Power %L, battery %B (%p%% load)")
        ((eq battery-status-function 'battery-pmset)
         "%L power, battery %B (%p%% load, remaining time %t)")
        (battery-status-function
***************
*** 276,282 ****
  
  (defun battery-linux-proc-acpi ()
    "Get ACPI status information from Linux kernel.
! This function works only with the new `/proc/acpi/' format introduced
  in Linux version 2.4.20 and 2.6.0.
  
  The following %-sequences are provided:
--- 282,288 ----
  
  (defun battery-linux-proc-acpi ()
    "Get ACPI status information from Linux kernel.
! This function works only with the `/proc/acpi/' format introduced
  in Linux version 2.4.20 and 2.6.0.
  
  The following %-sequences are provided:
***************
*** 390,395 ****
--- 396,480 ----
                       "N/A")))))
  
  
+ ;;; `/sys/class/power_supply/BATN' interface for Linux.
+ 
+ (defun battery-linux-sysfs ()
+   "Get ACPI status information from Linux kernel.
+ This function works only with the new `/sys/class/power_supply/BAT'
+ format introduced in Linux version 2.4.25.
+ 
+ The following %-sequences are provided:
+ %c Current capacity (mAh or mWh)
+ %B Battery status (verbose)
+ %p Battery load percentage
+ %L AC line status (verbose)"
+   (let (charging-state
+       (charge-full 0.0)
+       (charge-now 0.0)
+       (energy-full 0.0)
+       (energy-now 0.0))
+     ;; SysFS provides information about each battery present in the
+     ;; system in a separate subdirectory.  We are going to merge the
+     ;; available information together.
+     (with-temp-buffer
+       (dolist (dir (ignore-errors
+                   (directory-files
+                    "/sys/class/power_supply/" t "BAT[0-9]$")))
+       (erase-buffer)
+       (ignore-errors (insert-file-contents
+                       (expand-file-name "uevent" dir)))
+       (when (re-search-forward "POWER_SUPPLY_PRESENT=1$" nil t)
+         (goto-char (point-min))
+         (and (re-search-forward "POWER_SUPPLY_STATUS=\\(.*\\)$" nil t)
+              ;; On most multi-battery systems, most of the time only
+              ;; one battery is "charging"/"discharging", the others
+              ;; are "unknown".
+              (member charging-state '("Unknown" "Full" nil))
+              (setq charging-state (match-string 1)))
+         (let (full-string now-string)
+           ;; Sysfs may list either charge (mAh) or energy (mWh)
+           (cond ((and (re-search-forward
+                        "POWER_SUPPLY_CHARGE_FULL=\\([0-9]*\\)$" nil t)
+                       (setq full-string (match-string 1))
+                       (re-search-forward
+                        "POWER_SUPPLY_CHARGE_NOW=\\([0-9]*\\)$" nil t)
+                       (setq now-string (match-string 1)))
+                  (setq charge-full (+ charge-full
+                                       (string-to-number full-string))
+                        charge-now  (+ charge-now
+                                       (string-to-number now-string))))
+                 ((and (re-search-forward
+                        "POWER_SUPPLY_ENERGY_FULL=\\([0-9]*\\)$" nil t)
+                       (setq full-string (match-string 1))
+                       (re-search-forward
+                        "POWER_SUPPLY_ENERGY_NOW=\\([0-9]*\\)$" nil t)
+                       (setq now-string (match-string 1)))
+                  (setq energy-full (+ energy-full
+                                       (string-to-number full-string))
+                        energy-now  (+ energy-now
+                                       (string-to-number now-string)))))))))
+     (list (cons ?c (cond ((or (> charge-full  0) (> charge-now  0))
+                         (number-to-string charge-now))
+                        ((or (> energy-full  0) (> energy-now  0))
+                         (number-to-string energy-now))
+                        (t "N/A")))
+         (cons ?B (or charging-state "N/A"))
+         (cons ?p (cond ((> charge-full 0)
+                         (format "%.1f"
+                                 (/ (* 100 charge-now) charge-full)))
+                        ((> energy-full 0)
+                         (format "%.1f"
+                                 (/ (* 100 energy-now) energy-full)))
+                        (t "N/A")))
+         (cons ?L (if (file-readable-p "/sys/class/power_supply/AC/online")
+                      (if (battery-search-for-one-match-in-files
+                           "/sys/class/power_supply/AC/online" "1" 0)
+                          "AC"
+                        "BAT")
+                    "N/A")))))
+ 
+ 
+ 
  ;;; `pmset' interface for Darwin (OS X).
  
  (defun battery-pmset ()