Hi!
> This revamps the apm-emulation code to get suspend notifications
> regardless of what way pm_suspend() was invoked, whether via the
> apm ioctl or via /sys/power/state. Also do some code cleanup and
> add comments while at it.
Does this actually change user-kernel ABI?
> /*
> + * thread states (for threads using a writable /dev/apm_bios fd):
> + *
> + * SUSPEND_NONE: nothing happening
> + * SUSPEND_PENDING: suspend event queued for thread and pending to be read
> + * SUSPEND_READ: suspend event read, pending acknowledgement
> + * SUSPEND_ACKED: acknowledgement received from thread (via ioctl),
> + * waiting for resume
> + * SUSPEND_ACKTO: acknowledgement timeout
> + * SUSPEND_DONE: thread had acked suspend and is now notified of
> + * resume
> + *
> + * SUSPEND_WAIT: this thread invoked suspend and is waiting for resume
> + *
> + * A thread migrates in one of three paths:
> + * NONE -1-> PENDING -2-> READ -3-> ACKED -4-> DONE -5-> NONE
> + * -6-> ACKTO -7-> NONE
> + * NONE -8-> WAIT -9-> NONE
> + *
> + * While in PENDING or READ, the thread is accounted for in the
> + * suspend_acks_pending counter.
> + *
> + * The transitions are invoked as follows:
> + * 1: suspend event is signalled from the core PM code
> + * 2: the suspend event is read from the fd by the userspace thread
> + * 3: userspace thread issues the APM_IOC_SUSPEND ioctl (as ack)
> + * 4: core PM code signals that we have resumed
> + * 5: APM_IOC_SUSPEND ioctl returns
> + *
> + * 6: the notifier invoked from the core PM code timed out waiting
> + * for all relevant threds to enter ACKED state and puts those
> + * that haven't into ACKTO
> + * 7: those threads issue APM_IOC_SUSPEND ioctl too late,
> + * get an error
> + *
> + * 8: userspace thread issues the APM_IOC_SUSPEND ioctl (to suspend),
> + * ioctl code invokes pm_suspend()
> + * 9: pm_suspend() returns indicating resume
> + */
> +enum apm_suspend_state {
> + SUSPEND_NONE,
> + SUSPEND_PENDING,
> + SUSPEND_READ,
> + SUSPEND_ACKED,
> + SUSPEND_ACKTO,
> + SUSPEND_WAIT,
> + SUSPEND_DONE,
> +};
> +
> +/*
> * The per-file APM data
> */
> struct apm_user {
These are not passed to userspace, are they?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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