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    SubjectRe: pm_register() and pm_send_all()
    Date
    On Thursday, 13 of March 2008, Pavel Machek wrote:
    > On Wed 2008-03-12 15:00:42, Andrew Morton wrote:
    > >
    > > This:
    > >
    > > kernel/power/pm.c:203: warning: 'pm_register' is deprecated (declared at kernel/power/pm.c:62)
    > > kernel/power/pm.c:203: warning: 'pm_register' is deprecated (declared at kernel/power/pm.c:62)
    > > kernel/power/pm.c:204: warning: 'pm_send_all' is deprecated (declared at kernel/power/pm.c:178)
    > > kernel/power/pm.c:204: warning: 'pm_send_all' is deprecated (declared at kernel/power/pm.c:178)
    > >
    > > is getting a bit boring. These were marked deprecated at least three years
    > > ago.
    > >
    > >
    > > pm_register() no longer has any callers and afacit can be removed
    > > immediately.
    > >
    > > pm_send_all() has just a handful of callers:
    > >
    > > arch/x86/kernel/apm_32.c
    > > arch/mips/au1000/common/power.c
    > > arch/frv/kernel/pm.c
    >
    > AFAICT pm_send_all is a nop when noone uses pm_register...

    Apparently on 2.6.24 it's not used anywehere, at least according to LXR.

    > Hmm.. can we just force CONFIG_PM_LEGACY=n, and see what happens?

    Do you want me to push this patch and the following one from Ralf to Len?

    > Or maybe this is better idea? It may break build somewhere, but it
    > should be easy to fix... (it builds here, i386 and x86-64).
    >
    > Signed-off-by: Pavel Machek <pavel@suse.cz>
    >
    > diff --git a/arch/frv/kernel/pm.c b/arch/frv/kernel/pm.c
    > index c57ce3f..73f3aee 100644
    > --- a/arch/frv/kernel/pm.c
    > +++ b/arch/frv/kernel/pm.c
    > @@ -163,14 +163,11 @@ static int sysctl_pm_do_suspend(ctl_tabl
    > if ((mode != 1) && (mode != 5))
    > return -EINVAL;
    >
    > - retval = pm_send_all(PM_SUSPEND, (void *)3);
    > -
    > if (retval == 0) {
    > if (mode == 5)
    > retval = pm_do_bus_sleep();
    > else
    > retval = pm_do_suspend();
    > - pm_send_all(PM_RESUME, (void *)0);
    > }
    >
    > return retval;
    > @@ -183,9 +180,6 @@ static int try_set_cmode(int new_cmode)
    > if (!(clock_cmodes_permitted & (1<<new_cmode)))
    > return -EINVAL;
    >
    > - /* tell all the drivers we're suspending */
    > - pm_send_all(PM_SUSPEND, (void *)3);
    > -
    > /* now change cmode */
    > local_irq_disable();
    > frv_dma_pause_all();
    > @@ -201,8 +195,6 @@ #endif
    > frv_dma_resume_all();
    > local_irq_enable();
    >
    > - /* tell all the drivers we're resuming */
    > - pm_send_all(PM_RESUME, (void *)0);
    > return 0;
    > }
    >
    > diff --git a/arch/mips/au1000/common/power.c b/arch/mips/au1000/common/power.c
    > index 54047d6..a9f7f63 100644
    > --- a/arch/mips/au1000/common/power.c
    > +++ b/arch/mips/au1000/common/power.c
    > @@ -258,7 +258,6 @@ #endif
    > static int pm_do_sleep(ctl_table * ctl, int write, struct file *file,
    > void __user *buffer, size_t * len, loff_t *ppos)
    > {
    > - int retval = 0;
    > #ifdef SLEEP_TEST_TIMEOUT
    > #define TMPBUFLEN2 16
    > char buf[TMPBUFLEN2], *p;
    > @@ -278,33 +277,21 @@ #ifdef SLEEP_TEST_TIMEOUT
    > p = buf;
    > sleep_ticks = simple_strtoul(p, &p, 0);
    > #endif
    > - retval = pm_send_all(PM_SUSPEND, (void *) 2);
    > -
    > - if (retval)
    > - return retval;
    >
    > au_sleep();
    > - retval = pm_send_all(PM_RESUME, (void *) 0);
    > }
    > - return retval;
    > + return 0;
    > }
    >
    > static int pm_do_suspend(ctl_table * ctl, int write, struct file *file,
    > void __user *buffer, size_t * len, loff_t *ppos)
    > {
    > - int retval = 0;
    > -
    > if (!write) {
    > *len = 0;
    > } else {
    > - retval = pm_send_all(PM_SUSPEND, (void *) 2);
    > - if (retval)
    > - return retval;
    > suspend_mode = 1;
    > -
    > - retval = pm_send_all(PM_RESUME, (void *) 0);
    > }
    > - return retval;
    > + return 0;
    > }
    >
    >
    > diff --git a/arch/x86/kernel/apm_32.c b/arch/x86/kernel/apm_32.c
    > index d4438ef..d7e92bf 100644
    > --- a/arch/x86/kernel/apm_32.c
    > +++ b/arch/x86/kernel/apm_32.c
    > @@ -1189,19 +1189,6 @@ static int suspend(int vetoable)
    > int err;
    > struct apm_user *as;
    >
    > - if (pm_send_all(PM_SUSPEND, (void *)3)) {
    > - /* Vetoed */
    > - if (vetoable) {
    > - if (apm_info.connection_version > 0x100)
    > - set_system_power_state(APM_STATE_REJECT);
    > - err = -EBUSY;
    > - ignore_sys_suspend = 0;
    > - printk(KERN_WARNING "apm: suspend was vetoed.\n");
    > - goto out;
    > - }
    > - printk(KERN_CRIT "apm: suspend was vetoed, but suspending anyway.\n");
    > - }
    > -
    > device_suspend(PMSG_SUSPEND);
    > local_irq_disable();
    > device_power_down(PMSG_SUSPEND);
    > @@ -1224,7 +1211,6 @@ static int suspend(int vetoable)
    > device_power_up();
    > local_irq_enable();
    > device_resume();
    > - pm_send_all(PM_RESUME, (void *)0);
    > queue_event(APM_NORMAL_RESUME, NULL);
    > out:
    > spin_lock(&user_list_lock);
    > @@ -1337,7 +1323,6 @@ #endif
    > if ((event != APM_NORMAL_RESUME)
    > || (ignore_normal_resume == 0)) {
    > device_resume();
    > - pm_send_all(PM_RESUME, (void *)0);
    > queue_event(event, NULL);
    > }
    > ignore_normal_resume = 0;
    > diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
    > index e2d7b39..d6d8f8b 100644
    > --- a/kernel/power/Kconfig
    > +++ b/kernel/power/Kconfig
    > @@ -19,16 +19,6 @@ config PM
    > will issue the hlt instruction if nothing is to be done, thereby
    > sending the processor to sleep and saving power.
    >
    > -config PM_LEGACY
    > - bool "Legacy Power Management API (DEPRECATED)"
    > - depends on PM
    > - default n
    > - ---help---
    > - Support for pm_register() and friends. This old API is obsoleted
    > - by the driver model.
    > -
    > - If unsure, say N.
    > -
    > config PM_DEBUG
    > bool "Power Management Debug Support"
    > depends on PM
    > diff --git a/kernel/power/Makefile b/kernel/power/Makefile
    > index e5693d6..523abb9 100644
    > --- a/kernel/power/Makefile
    > +++ b/kernel/power/Makefile
    > @@ -4,7 +4,6 @@ EXTRA_CFLAGS += -DDEBUG
    > endif
    >
    > obj-y := main.o
    > -obj-$(CONFIG_PM_LEGACY) += pm.o
    > obj-$(CONFIG_PM_SLEEP) += process.o console.o sleepy.o
    > obj-$(CONFIG_HIBERNATION) += swsusp.o disk.o snapshot.o swap.o user.o
    >
    > diff --git a/kernel/power/pm.c b/kernel/power/pm.c
    > deleted file mode 100644
    > index 60c73fa..0000000
    > --- a/kernel/power/pm.c
    > +++ /dev/null
    > @@ -1,205 +0,0 @@
    > -/*
    > - * pm.c - Power management interface
    > - *
    > - * Copyright (C) 2000 Andrew Henroid
    > - *
    > - * This program is free software; you can redistribute it and/or modify
    > - * it under the terms of the GNU General Public License as published by
    > - * the Free Software Foundation; either version 2 of the License, or
    > - * (at your option) any later version.
    > - *
    > - * This program is distributed in the hope that it will be useful,
    > - * but WITHOUT ANY WARRANTY; without even the implied warranty of
    > - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    > - * GNU General Public License for more details.
    > - *
    > - * You should have received a copy of the GNU General Public License
    > - * along with this program; if not, write to the Free Software
    > - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
    > - */
    > -#include <linux/init.h>
    > -#include <linux/module.h>
    > -#include <linux/spinlock.h>
    > -#include <linux/mm.h>
    > -#include <linux/slab.h>
    > -#include <linux/pm.h>
    > -#include <linux/pm_legacy.h>
    > -#include <linux/interrupt.h>
    > -#include <linux/mutex.h>
    > -
    > -/*
    > - * Locking notes:
    > - * pm_devs_lock can be a semaphore providing pm ops are not called
    > - * from an interrupt handler (already a bad idea so no change here). Each
    > - * change must be protected so that an unlink of an entry doesn't clash
    > - * with a pm send - which is permitted to sleep in the current architecture
    > - *
    > - * Module unloads clashing with pm events now work out safely, the module
    > - * unload path will block until the event has been sent. It may well block
    > - * until a resume but that will be fine.
    > - */
    > -
    > -static DEFINE_MUTEX(pm_devs_lock);
    > -static LIST_HEAD(pm_devs);
    > -
    > -/**
    > - * pm_register - register a device with power management
    > - * @type: device type
    > - * @id: device ID
    > - * @callback: callback function
    > - *
    > - * Add a device to the list of devices that wish to be notified about
    > - * power management events. A &pm_dev structure is returned on success,
    > - * on failure the return is %NULL.
    > - *
    > - * The callback function will be called in process context and
    > - * it may sleep.
    > - */
    > -
    > -struct pm_dev *pm_register(pm_dev_t type,
    > - unsigned long id,
    > - pm_callback callback)
    > -{
    > - struct pm_dev *dev = kzalloc(sizeof(struct pm_dev), GFP_KERNEL);
    > - if (dev) {
    > - dev->type = type;
    > - dev->id = id;
    > - dev->callback = callback;
    > -
    > - mutex_lock(&pm_devs_lock);
    > - list_add(&dev->entry, &pm_devs);
    > - mutex_unlock(&pm_devs_lock);
    > - }
    > - return dev;
    > -}
    > -
    > -/**
    > - * pm_send - send request to a single device
    > - * @dev: device to send to
    > - * @rqst: power management request
    > - * @data: data for the callback
    > - *
    > - * Issue a power management request to a given device. The
    > - * %PM_SUSPEND and %PM_RESUME events are handled specially. The
    > - * data field must hold the intended next state. No call is made
    > - * if the state matches.
    > - *
    > - * BUGS: what stops two power management requests occurring in parallel
    > - * and conflicting.
    > - *
    > - * WARNING: Calling pm_send directly is not generally recommended, in
    > - * particular there is no locking against the pm_dev going away. The
    > - * caller must maintain all needed locking or have 'inside knowledge'
    > - * on the safety. Also remember that this function is not locked against
    > - * pm_unregister. This means that you must handle SMP races on callback
    > - * execution and unload yourself.
    > - */
    > -
    > -static int pm_send(struct pm_dev *dev, pm_request_t rqst, void *data)
    > -{
    > - int status = 0;
    > - unsigned long prev_state, next_state;
    > -
    > - if (in_interrupt())
    > - BUG();
    > -
    > - switch (rqst) {
    > - case PM_SUSPEND:
    > - case PM_RESUME:
    > - prev_state = dev->state;
    > - next_state = (unsigned long) data;
    > - if (prev_state != next_state) {
    > - if (dev->callback)
    > - status = (*dev->callback)(dev, rqst, data);
    > - if (!status) {
    > - dev->state = next_state;
    > - dev->prev_state = prev_state;
    > - }
    > - }
    > - else {
    > - dev->prev_state = prev_state;
    > - }
    > - break;
    > - default:
    > - if (dev->callback)
    > - status = (*dev->callback)(dev, rqst, data);
    > - break;
    > - }
    > - return status;
    > -}
    > -
    > -/*
    > - * Undo incomplete request
    > - */
    > -static void pm_undo_all(struct pm_dev *last)
    > -{
    > - struct list_head *entry = last->entry.prev;
    > - while (entry != &pm_devs) {
    > - struct pm_dev *dev = list_entry(entry, struct pm_dev, entry);
    > - if (dev->state != dev->prev_state) {
    > - /* previous state was zero (running) resume or
    > - * previous state was non-zero (suspended) suspend
    > - */
    > - pm_request_t undo = (dev->prev_state
    > - ? PM_SUSPEND:PM_RESUME);
    > - pm_send(dev, undo, (void*) dev->prev_state);
    > - }
    > - entry = entry->prev;
    > - }
    > -}
    > -
    > -/**
    > - * pm_send_all - send request to all managed devices
    > - * @rqst: power management request
    > - * @data: data for the callback
    > - *
    > - * Issue a power management request to a all devices. The
    > - * %PM_SUSPEND events are handled specially. Any device is
    > - * permitted to fail a suspend by returning a non zero (error)
    > - * value from its callback function. If any device vetoes a
    > - * suspend request then all other devices that have suspended
    > - * during the processing of this request are restored to their
    > - * previous state.
    > - *
    > - * WARNING: This function takes the pm_devs_lock. The lock is not dropped until
    > - * the callbacks have completed. This prevents races against pm locking
    > - * functions, races against module unload pm_unregister code. It does
    > - * mean however that you must not issue pm_ functions within the callback
    > - * or you will deadlock and users will hate you.
    > - *
    > - * Zero is returned on success. If a suspend fails then the status
    > - * from the device that vetoes the suspend is returned.
    > - *
    > - * BUGS: what stops two power management requests occurring in parallel
    > - * and conflicting.
    > - */
    > -
    > -int pm_send_all(pm_request_t rqst, void *data)
    > -{
    > - struct list_head *entry;
    > -
    > - mutex_lock(&pm_devs_lock);
    > - entry = pm_devs.next;
    > - while (entry != &pm_devs) {
    > - struct pm_dev *dev = list_entry(entry, struct pm_dev, entry);
    > - if (dev->callback) {
    > - int status = pm_send(dev, rqst, data);
    > - if (status) {
    > - /* return devices to previous state on
    > - * failed suspend request
    > - */
    > - if (rqst == PM_SUSPEND)
    > - pm_undo_all(dev);
    > - mutex_unlock(&pm_devs_lock);
    > - return status;
    > - }
    > - }
    > - entry = entry->next;
    > - }
    > - mutex_unlock(&pm_devs_lock);
    > - return 0;
    > -}
    > -
    > -EXPORT_SYMBOL(pm_register);
    > -EXPORT_SYMBOL(pm_send_all);
    > -


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