Messages in this thread Patch in this message | | | Date | Fri, 20 Jul 2012 20:33:32 +0800 | Subject | [RFC] firmware load: defer request_firmware during early boot and resume | From | Ming Lei <> |
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The RFC patch is just for discussing if the idea of deferring request_firmware is doable for addressing the issue of request_firmware in resume path, which is caused by driver unbind/rebind during resume.
At least usb bus is involved in such things, one driver may be unbound and rebound in resume path at several situations, and request_firmware is often called inside probe().
Also the idea should be helpful for other hotplug buses too, at least there was the similar problem report on pcmcia bus.
diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 6cd2c6c..fb02eff 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -123,7 +123,7 @@ static bool driver_deferred_probe_enable = false; * list and schedules the deferred probe workqueue to process them. It * should be called anytime a driver is successfully bound to a device. */ -static void driver_deferred_probe_trigger(void) +void driver_deferred_probe_trigger(void) { if (!driver_deferred_probe_enable) return; @@ -144,6 +144,7 @@ static void driver_deferred_probe_trigger(void) */ queue_work(deferred_wq, &deferred_probe_work); } +EXPORT_SYMBOL_GPL(driver_deferred_probe_trigger);
/** * deferred_probe_initcall() - Enable probing of deferred devices diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c index 5401814..4fe742f 100644 --- a/drivers/base/firmware_class.c +++ b/drivers/base/firmware_class.c @@ -593,6 +593,9 @@ request_firmware(const struct firmware **firmware_p, const char *name, if (IS_ERR_OR_NULL(fw_priv)) return PTR_RET(fw_priv);
+ if (system_state != SYSTEM_RUNNING) + return -EPROBE_DEFER; + ret = usermodehelper_read_trylock(); if (WARN_ON(ret)) { dev_err(device, "firmware: %s will not be loaded\n", name); diff --git a/include/linux/device.h b/include/linux/device.h index d0e4d99..a63d3171 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -244,7 +244,7 @@ extern struct device_driver *driver_find(const char *name, struct bus_type *bus); extern int driver_probe_done(void); extern void wait_for_device_probe(void); - +extern void driver_deferred_probe_trigger(void);
/* sysfs interface for exporting driver attributes */
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index e07f5e0..c8d74c6 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -378,6 +378,7 @@ extern enum system_states { SYSTEM_POWER_OFF, SYSTEM_RESTART, SYSTEM_SUSPEND_DISK, + SYSTEM_SUSPEND, } system_state;
#define TAINT_PROPRIETARY_MODULE 0 diff --git a/init/main.c b/init/main.c index e60679d..237eae1 100644 --- a/init/main.c +++ b/init/main.c @@ -809,6 +809,8 @@ static noinline int init_post(void) current->signal->flags |= SIGNAL_UNKILLABLE; flush_delayed_fput();
+ driver_deferred_probe_trigger(); + if (ramdisk_execute_command) { run_init_process(ramdisk_execute_command); printk(KERN_WARNING "Failed to execute %s\n", diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 1da39ea..dbf6ffb 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -224,6 +224,9 @@ int suspend_devices_and_enter(suspend_state_t state) goto Recover_platform; } suspend_test_finish("suspend devices"); + + system_state = SYSTEM_SUSPEND; + if (suspend_test(TEST_DEVICES)) goto Recover_platform;
@@ -301,6 +304,10 @@ static int enter_state(suspend_state_t state) Finish: pr_debug("PM: Finishing wakeup.\n"); suspend_finish(); + + system_state = SYSTEM_RUNNING; + driver_deferred_probe_trigger(); + Unlock: mutex_unlock(&pm_mutex); return error;
Thanks, -- Ming Lei
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