Re: [linux-pm] [patch] pm: fix runtime powermanagement's /sys interface

Pavel Machek
2006-01-05T22:59:35Z

On Čt 05-01-06 23:27:05, Dominik Brodowski wrote:
> On Thu, Jan 05, 2006 at 11:23:38PM +0100, Pavel Machek wrote:
> > > In addition, your patch breaks pcmcia / pcmciautils which already uses
> > > numbers (which I already had to change from "3" to "2" before...).
> >
> > pcmcia actually uses this? Ouch. Do you just read the power file, or
> > do you write to it, too?
>
> Reading and writing. Replacement for "cardctl suspend" and "cardctl resume".
>
>
> static int pccardctl_power_one(unsigned long socket_no, unsigned int device,
> unsigned int power)
> {
> int ret;
> char file[SYSFS_PATH_MAX];
> struct sysfs_attribute *attr;
>
> snprintf(file, SYSFS_PATH_MAX,
> "/sys/bus/pcmcia/devices/%lu.%u/power/state",
> socket_no, device);
>
> attr = sysfs_open_attribute(file);
> if (!attr)
> return -ENODEV;
>
> ret = sysfs_write_attribute(attr, power ? "2" : "0", 1);
>
> sysfs_close_attribute(attr);
>
> return (ret);
> }
>
>
> NB: it will break one day, one way or another, when gregkh makes the
> /sys/class -> /sys/devices conversion. However, I'd want to try not to break
> the new pcmciautils userspace too often...

Do you know how soon that day is?

I'd really like to change it into strings so that interface will not
have to change when/if someone will introduce multiple power states.

I could accept both "0" and "on" on input, but have to output single
value.
Pavel

--
Thanks, Sharp!