On Sunday 20 January 2008, Rafael J. Wysocki wrote:
> On Sunday, 13 of January 2008, Alan Stern wrote:
> > On Sun, 13 Jan 2008, Michael Buesch wrote:
> >
> > > > Besides, if you're going to register the device right back again during
> > > > the subsequent resume, then why go to the trouble of unregistering it
> > > > during suspend? Why not just leave it registered the whole time and
> > > > avoid all the complication (and excess meaningless uevents)?
> > >
> > > Well, because not doing it complicates code :)
> > > Currently suspend/resume calls the same code as init/exit.
> > > The b43 init/exit code is really complicated, compared to other
> > > drivers, due to dozens of hardware versions. So I just avoided
> > > having yet other codepaths for suspend/resume. But I will add
> > > a flag to the device structure that's used to avoid unregistering stuff.
> >
> > Instead of adding an extra flag you should refactor the code. Have a
> > common "enable" subroutine that can be called for both init and resume,
> > and a common "disable" subroutine that can be called for both exit and
> > suspend. Then the method routines themselves will contain only the
> > portions unique to their particular functions, making them shorter and
> > simpler.
>
> Well, it doesn't seem to be that easy.
>
> I tried to fix the issue myself and finally obtained the appended, apparently
> working, patch (against 2.6.24-rc8-mm1). Well, it should have been a series
> of patches against multiple subsystems, but I thought it would be instructive
> to put everything needed into one bigger patch for starters.
>
> Greetings,
> Rafael
>
> ---
> drivers/base/power/main.c | 1
> drivers/base/power/power.h | 1
> drivers/char/hw_random/core.c | 10 ++++-----
> drivers/char/misc.c | 13 ++++++++----
> drivers/leds/led-class.c | 13 ++++++++----
> drivers/net/wireless/b43/leds.c | 17 +++++++++------
> drivers/net/wireless/b43/leds.h | 14 +++++++++++--
> drivers/net/wireless/b43/main.c | 43
> +++++++++++++++++++++++++++++-----------
> include/linux/device.h | 6 +++++
> include/linux/hw_random.h | 10 ++++++++-
> include/linux/leds.h | 10 ++++++++-
> include/linux/miscdevice.h | 10 ++++++++-
> 12 files changed, 111 insertions(+), 37 deletions(-)
>
> Index: linux-2.6.24-rc8-mm1/drivers/net/wireless/b43/main.c
> ===================================================================
> --- linux-2.6.24-rc8-mm1.orig/drivers/net/wireless/b43/main.c
> +++ linux-2.6.24-rc8-mm1/drivers/net/wireless/b43/main.c
> @@ -2470,10 +2470,15 @@ static int b43_rng_read(struct hwrng *rn
> return (sizeof(u16));
> }
>
> -static void b43_rng_exit(struct b43_wl *wl)
> +static void __b43_rng_exit(struct b43_wl *wl, bool suspended)
> {
> if (wl->rng_initialized)
> - hwrng_unregister(&wl->rng);
> + __hwrng_unregister(&wl->rng, suspended);
> +}
> +
> +static void b43_rng_exit(struct b43_wl *wl)
> +{
> + __b43_rng_exit(wl, false);
> }
>
> static int b43_rng_init(struct b43_wl *wl)
> @@ -3289,7 +3294,7 @@ static void b43_set_retry_limits(struct
>
> /* Shutdown a wireless core */
> /* Locking: wl->mutex */
> -static void b43_wireless_core_exit(struct b43_wldev *dev)
> +static void __b43_wireless_core_exit(struct b43_wldev *dev, bool no_suspend)
> {
> struct b43_phy *phy = &dev->phy;
>
> @@ -3298,8 +3303,10 @@ static void b43_wireless_core_exit(struc
> return;
> b43_set_status(dev, B43_STAT_UNINIT);
>
> - b43_leds_exit(dev);
> - b43_rng_exit(dev->wl);
> + if (no_suspend) {
> + b43_leds_exit(dev);
> + b43_rng_exit(dev->wl);
> + }
> b43_pio_free(dev);
> b43_dma_free(dev);
> b43_chip_exit(dev);
> @@ -3313,8 +3320,13 @@ static void b43_wireless_core_exit(struc
> ssb_bus_may_powerdown(dev->dev->bus);
> }
>
> +static void b43_wireless_core_exit(struct b43_wldev *dev)
> +{
> + __b43_wireless_core_exit(dev, true);
> +}
Nah, please don't obfuscate the code.
Better add a flag to struct b43_wldev and check that in the few places
that need different behaviour.
> /* Initialize a wireless core */
> -static int b43_wireless_core_init(struct b43_wldev *dev)
> +static int __b43_wireless_core_init(struct b43_wldev *dev, bool no_suspend)
> {
> struct b43_wl *wl = dev->wl;
> struct ssb_bus *bus = dev->dev->bus;
> @@ -3420,11 +3432,13 @@ static int b43_wireless_core_init(struct
> memset(wl->mac_addr, 0, ETH_ALEN);
> b43_upload_card_macaddress(dev);
> b43_security_init(dev);
> - b43_rng_init(wl);
> + if (no_suspend)
> + b43_rng_init(wl);
>
> b43_set_status(dev, B43_STAT_INITIALIZED);
>
> - b43_leds_init(dev);
> + if (no_suspend)
> + b43_leds_init(dev);
> out:
> return err;
>
> @@ -3442,6 +3456,11 @@ out:
> return err;
> }
>
> +static int b43_wireless_core_init(struct b43_wldev *dev)
> +{
> + return __b43_wireless_core_init(dev, true);
> +}
> +
> static int b43_op_add_interface(struct ieee80211_hw *hw,
> struct ieee80211_if_init_conf *conf)
> {
> @@ -4028,7 +4047,7 @@ static int b43_suspend(struct ssb_device
> if (wldev->suspend_init_status >= B43_STAT_STARTED)
> b43_wireless_core_stop(wldev);
> if (wldev->suspend_init_status >= B43_STAT_INITIALIZED)
> - b43_wireless_core_exit(wldev);
> + __b43_wireless_core_exit(wldev, false);
> mutex_unlock(&wl->mutex);
>
> b43dbg(wl, "Device suspended.\n");
> @@ -4046,7 +4065,7 @@ static int b43_resume(struct ssb_device
>
> mutex_lock(&wl->mutex);
> if (wldev->suspend_init_status >= B43_STAT_INITIALIZED) {
> - err = b43_wireless_core_init(wldev);
> + err = __b43_wireless_core_init(wldev, false);
> if (err) {
> b43err(wl, "Resume failed at core init\n");
> goto out;
> @@ -4055,7 +4074,9 @@ static int b43_resume(struct ssb_device
> if (wldev->suspend_init_status >= B43_STAT_STARTED) {
> err = b43_wireless_core_start(wldev);
> if (err) {
> - b43_wireless_core_exit(wldev);
> + b43_leds_resume_exit(wldev);
> + __b43_rng_exit(wldev->wl, true);
> + __b43_wireless_core_exit(wldev, false);
> b43err(wl, "Resume failed at core start\n");
> goto out;
> }
> Index: linux-2.6.24-rc8-mm1/drivers/net/wireless/b43/leds.h
> ===================================================================
> --- linux-2.6.24-rc8-mm1.orig/drivers/net/wireless/b43/leds.h
> +++ linux-2.6.24-rc8-mm1/drivers/net/wireless/b43/leds.h
> @@ -43,8 +43,15 @@ enum b43_led_behaviour {
> };
>
> void b43_leds_init(struct b43_wldev *dev);
> -void b43_leds_exit(struct b43_wldev *dev);
> -
> +void __b43_leds_exit(struct b43_wldev *dev, bool suspended);
> +static inline void b43_leds_exit(struct b43_wldev *dev)
> +{
> + __b43_leds_exit(dev, false);
> +}
> +static inline void b43_leds_resume_exit(struct b43_wldev *dev)
> +{
> + __b43_leds_exit(dev, true);
> +}
No obfuscation please.
> #else /* CONFIG_B43_LEDS */
> /* LED support disabled */
> @@ -59,6 +66,9 @@ static inline void b43_leds_init(struct
> static inline void b43_leds_exit(struct b43_wldev *dev)
> {
> }
> +static inline void b43_leds_resume_exit(struct b43_wldev *dev)
> +{
> +}
> #endif /* CONFIG_B43_LEDS */
>
> #endif /* B43_LEDS_H_ */
> Index: linux-2.6.24-rc8-mm1/drivers/net/wireless/b43/leds.c
> ===================================================================
> --- linux-2.6.24-rc8-mm1.orig/drivers/net/wireless/b43/leds.c
> +++ linux-2.6.24-rc8-mm1/drivers/net/wireless/b43/leds.c
> @@ -112,11 +112,14 @@ static int b43_register_led(struct b43_w
> return 0;
> }
>
> -static void b43_unregister_led(struct b43_led *led)
> +static void b43_unregister_led(struct b43_led *led, bool suspended)
> {
> if (!led->dev)
> return;
> - led_classdev_unregister(&led->led_dev);
> + if (suspended)
> + led_classdev_unregister_suspended(&led->led_dev);
> + else
> + led_classdev_unregister(&led->led_dev);
> b43_led_turn_off(led->dev, led->index, led->activelow);
> led->dev = NULL;
> }
> @@ -230,10 +233,10 @@ void b43_leds_init(struct b43_wldev *dev
> }
> }
>
> -void b43_leds_exit(struct b43_wldev *dev)
> +void __b43_leds_exit(struct b43_wldev *dev, bool suspended)
> {
> - b43_unregister_led(&dev->led_tx);
> - b43_unregister_led(&dev->led_rx);
> - b43_unregister_led(&dev->led_assoc);
> - b43_unregister_led(&dev->led_radio);
> + b43_unregister_led(&dev->led_tx, suspended);
> + b43_unregister_led(&dev->led_rx, suspended);
> + b43_unregister_led(&dev->led_assoc, suspended);
> + b43_unregister_led(&dev->led_radio, suspended);
> }
> Index: linux-2.6.24-rc8-mm1/drivers/leds/led-class.c
> ===================================================================
> --- linux-2.6.24-rc8-mm1.orig/drivers/leds/led-class.c
> +++ linux-2.6.24-rc8-mm1/drivers/leds/led-class.c
> @@ -137,12 +137,14 @@ err_out:
> EXPORT_SYMBOL_GPL(led_classdev_register);
>
> /**
> - * led_classdev_unregister - unregisters a object of led_properties class.
> + * __led_classdev_unregister - unregisters a object of led_properties class.
> * @led_cdev: the led device to unregister
> + * @suspended: indicates whether system-wide suspend or resume is in progress
> *
> * Unregisters a previously registered via led_classdev_register object.
> */
> -void led_classdev_unregister(struct led_classdev *led_cdev)
> +void __led_classdev_unregister(struct led_classdev *led_cdev,
> + bool suspended)
> {
> device_remove_file(led_cdev->dev, &dev_attr_brightness);
> #ifdef CONFIG_LEDS_TRIGGERS
> @@ -153,13 +155,16 @@ void led_classdev_unregister(struct led_
> up_write(&led_cdev->trigger_lock);
> #endif
>
> - device_unregister(led_cdev->dev);
> + if (suspended)
> + device_pm_schedule_removal(led_cdev->dev);
> + else
> + device_unregister(led_cdev->dev);
>
> down_write(&leds_list_lock);
> list_del(&led_cdev->node);
> up_write(&leds_list_lock);
> }
> -EXPORT_SYMBOL_GPL(led_classdev_unregister);
> +EXPORT_SYMBOL_GPL(__led_classdev_unregister);
>
> static int __init leds_init(void)
> {
> Index: linux-2.6.24-rc8-mm1/include/linux/leds.h
> ===================================================================
> --- linux-2.6.24-rc8-mm1.orig/include/linux/leds.h
> +++ linux-2.6.24-rc8-mm1/include/linux/leds.h
> @@ -59,7 +59,15 @@ struct led_classdev {
>
> extern int led_classdev_register(struct device *parent,
> struct led_classdev *led_cdev);
> -extern void led_classdev_unregister(struct led_classdev *led_cdev);
> +extern void __led_classdev_unregister(struct led_classdev *led_cdev, bool
> sus);
> +static inline void led_classdev_unregister(struct led_classdev *lcd)
> +{
> + __led_classdev_unregister(lcd, false);
> +}
> +static inline void led_classdev_unregister_suspended(struct led_classdev
> *lcd)
> +{
> + __led_classdev_unregister(lcd, true);
> +}
> extern void led_classdev_suspend(struct led_classdev *led_cdev);
> extern void led_classdev_resume(struct led_classdev *led_cdev);
>
> Index: linux-2.6.24-rc8-mm1/drivers/base/power/main.c
> ===================================================================
> --- linux-2.6.24-rc8-mm1.orig/drivers/base/power/main.c
> +++ linux-2.6.24-rc8-mm1/drivers/base/power/main.c
> @@ -129,6 +129,7 @@ void device_pm_schedule_removal(struct d
> list_move_tail(&dev->power.entry, &dpm_destroy);
> mutex_unlock(&dpm_list_mtx);
> }
> +EXPORT_SYMBOL_GPL(device_pm_schedule_removal);
>
> /**
> * pm_sleep_lock - mutual exclusion for registration and suspend
> Index: linux-2.6.24-rc8-mm1/include/linux/device.h
> ===================================================================
> --- linux-2.6.24-rc8-mm1.orig/include/linux/device.h
> +++ linux-2.6.24-rc8-mm1/include/linux/device.h
> @@ -532,11 +532,17 @@ extern struct device *device_create(stru
> extern void device_destroy(struct class *cls, dev_t devt);
> #ifdef CONFIG_PM_SLEEP
> extern void destroy_suspended_device(struct class *cls, dev_t devt);
> +extern void device_pm_schedule_removal(struct device *);
> #else /* !CONFIG_PM_SLEEP */
> static inline void destroy_suspended_device(struct class *cls, dev_t devt)
> {
> device_destroy(cls, devt);
> }
> +
> +static inline void device_pm_schedule_removal(struct device *dev)
> +{
> + device_unregister(dev);
> +}
> #endif /* !CONFIG_PM_SLEEP */
>
> /*
> Index: linux-2.6.24-rc8-mm1/drivers/base/power/power.h
> ===================================================================
> --- linux-2.6.24-rc8-mm1.orig/drivers/base/power/power.h
> +++ linux-2.6.24-rc8-mm1/drivers/base/power/power.h
> @@ -13,7 +13,6 @@ static inline struct device *to_device(s
>
> extern void device_pm_add(struct device *);
> extern void device_pm_remove(struct device *);
> -extern void device_pm_schedule_removal(struct device *);
> extern int pm_sleep_lock(void);
> extern void pm_sleep_unlock(void);
>
> Index: linux-2.6.24-rc8-mm1/drivers/char/misc.c
> ===================================================================
> --- linux-2.6.24-rc8-mm1.orig/drivers/char/misc.c
> +++ linux-2.6.24-rc8-mm1/drivers/char/misc.c
> @@ -232,8 +232,9 @@ int misc_register(struct miscdevice * mi
> }
>
> /**
> - * misc_deregister - unregister a miscellaneous device
> + * __misc_deregister - unregister a miscellaneous device
> * @misc: device to unregister
> + * @suspended: to be set if the function is used during suspend/resume
> *
> * Unregister a miscellaneous device that was previously
> * successfully registered with misc_register(). Success
> @@ -241,7 +242,7 @@ int misc_register(struct miscdevice * mi
> * indicates an error.
> */
>
> -int misc_deregister(struct miscdevice * misc)
> +int __misc_deregister(struct miscdevice *misc, bool suspended)
> {
> int i = misc->minor;
>
> @@ -250,7 +251,11 @@ int misc_deregister(struct miscdevice *
>
> mutex_lock(&misc_mtx);
> list_del(&misc->list);
> - device_destroy(misc_class, MKDEV(MISC_MAJOR, misc->minor));
> + if (suspended)
> + destroy_suspended_device(misc_class,
> + MKDEV(MISC_MAJOR, misc->minor));
> + else
> + device_destroy(misc_class, MKDEV(MISC_MAJOR, misc->minor));
> if (i < DYNAMIC_MINORS && i>0) {
> misc_minors[i>>3] &= ~(1 << (misc->minor & 7));
> }
> @@ -259,7 +264,7 @@ int misc_deregister(struct miscdevice *
> }
>
> EXPORT_SYMBOL(misc_register);
> -EXPORT_SYMBOL(misc_deregister);
> +EXPORT_SYMBOL(__misc_deregister);
>
> static int __init misc_init(void)
> {
> Index: linux-2.6.24-rc8-mm1/include/linux/miscdevice.h
> ===================================================================
> --- linux-2.6.24-rc8-mm1.orig/include/linux/miscdevice.h
> +++ linux-2.6.24-rc8-mm1/include/linux/miscdevice.h
> @@ -43,7 +43,15 @@ struct miscdevice {
> };
>
> extern int misc_register(struct miscdevice * misc);
> -extern int misc_deregister(struct miscdevice * misc);
> +extern int __misc_deregister(struct miscdevice *misc, bool suspended);
> +static inline int misc_deregister(struct miscdevice *misc)
> +{
> + return __misc_deregister(misc, false);
> +}
> +static inline int misc_deregister_suspended(struct miscdevice *misc)
> +{
> + return __misc_deregister(misc, true);
> +}
>
> #define MODULE_ALIAS_MISCDEV(minor) \
> MODULE_ALIAS("char-major-" __stringify(MISC_MAJOR) \
> Index: linux-2.6.24-rc8-mm1/drivers/char/hw_random/core.c
> ===================================================================
> --- linux-2.6.24-rc8-mm1.orig/drivers/char/hw_random/core.c
> +++ linux-2.6.24-rc8-mm1/drivers/char/hw_random/core.c
> @@ -234,11 +234,11 @@ static DEVICE_ATTR(rng_available, S_IRUG
> NULL);
>
>
> -static void unregister_miscdev(void)
> +static void unregister_miscdev(bool suspended)
> {
> device_remove_file(rng_miscdev.this_device, &dev_attr_rng_available);
> device_remove_file(rng_miscdev.this_device, &dev_attr_rng_current);
> - misc_deregister(&rng_miscdev);
> + __misc_deregister(&rng_miscdev, suspended);
> }
>
> static int register_miscdev(void)
> @@ -313,7 +313,7 @@ out:
> }
> EXPORT_SYMBOL_GPL(hwrng_register);
>
> -void hwrng_unregister(struct hwrng *rng)
> +void __hwrng_unregister(struct hwrng *rng, bool suspended)
> {
> int err;
>
> @@ -332,11 +332,11 @@ void hwrng_unregister(struct hwrng *rng)
> }
> }
> if (list_empty(&rng_list))
> - unregister_miscdev();
> + unregister_miscdev(suspended);
>
> mutex_unlock(&rng_mutex);
> }
> -EXPORT_SYMBOL_GPL(hwrng_unregister);
> +EXPORT_SYMBOL_GPL(__hwrng_unregister);
>
>
> MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver");
> Index: linux-2.6.24-rc8-mm1/include/linux/hw_random.h
> ===================================================================
> --- linux-2.6.24-rc8-mm1.orig/include/linux/hw_random.h
> +++ linux-2.6.24-rc8-mm1/include/linux/hw_random.h
> @@ -44,7 +44,15 @@ struct hwrng {
> /** Register a new Hardware Random Number Generator driver. */
> extern int hwrng_register(struct hwrng *rng);
> /** Unregister a Hardware Random Number Generator driver. */
> -extern void hwrng_unregister(struct hwrng *rng);
> +extern void __hwrng_unregister(struct hwrng *rng, bool suspended);
> +static inline void hwrng_unregister(struct hwrng *rng)
> +{
> + __hwrng_unregister(rng, false);
> +}
> +static inline void hwrng_unregister_suspended(struct hwrng *rng)
> +{
> + __hwrng_unregister(rng, true);
> +}
>
> #endif /* __KERNEL__ */
> #endif /* LINUX_HWRANDOM_H_ */
>
>
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