Minor improvement to acpiconf

[Nate Lawson]

M. Warner Losh wrote:
> acpiconf -i 0 now prints more information about the battery from the bst:
> 	Rate of discharge
> 	Present Capacity
> 	Current Voltage
-------------------------------------------------
> 
> --- /dell/imp/FreeBSD/src/usr.sbin/acpi/acpiconf/acpiconf.c	Wed Aug 18 16:14:43 2004
> +++ ./acpiconf.c	Mon Nov 15 23:12:50 2004
> @@ -45,8 +45,8 @@
>  
>  static int	acpifd;
>  
> -static int
> -acpi_init()
> +static void
> +acpi_init(void)
>  {

Why the change to void if it still returns 0?

>  	acpifd = open(ACPIDEV, O_RDWR);
>  	if (acpifd == -1){
> @@ -117,6 +117,17 @@
>  	printf("Type:\t\t\t%s\n", battio.bif.type);
>  	printf("OEM info:\t\t%s\n", battio.bif.oeminfo);
>  
> +	if (ioctl(acpifd, ACPIIO_CMBAT_GET_BST, &battio) == -1)
> +		err(EX_IOERR, "get battery info (%d) failed", num);
> +
> +	if (battio.bst.state != ACPI_BATT_STAT_NOT_PRESENT) {

Prefer positive logic.

> +		printf("State:\t\t\tPresent\n");
> +		printf("Rate:\t\t\t%d mWh\n", battio.bst.rate);
> +		printf("Cap:\t\t\t%d mWh\n", battio.bst.cap);
> +		printf("Volt:\t\t\t%d mV\n", battio.bst.volt);

I agree with these except for a slight misgiving about "cap".  That 
information is already exported via sysctl and if we have to export the 
same thing different ways, I think the interface is not optimal.

In general, I'd like to move away from acpi-specific ioctls.  There 
should be just one way of getting the battery info and it shouldn't 
refer to the underlying method names (_BST and _BIF) like the current 
ones do.  Mike made a good case for eliminating the dev_t entirely since 
there is never any IO for acpi, it's all control traffic.  Sysctl seems 
more appropriate for that than creating a device that will never see a 
read, write, or other access other than ioctl().  But this is a 
complaint about the current design and the half-ioctl, half-sysctl 
implementation.

You're not making it worse so go ahead and commit.  I'm just hoping 
someone will consider improving the interface in the future.

-Nate