| Message ID | 1443517859-30376-20-git-send-email-tomeu.vizoso@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 9/29/2015 2:10 AM, Tomeu Vizoso wrote: > Add a field to struct device that instructs the device-driver core to > defer the probe of this device until the late_initcall level. > > By letting all built-in drivers to register before starting to probe, we > can avoid any deferred probes by probing dependencies on demand. > > Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> > > --- > > Changes in v7: > - Move IS_ENABLED(CONFIG_DELAY_DEVICE_PROBES) into if condition > - Hide CONFIG_DELAY_DEVICE_PROBES behind EXPERT > > Changes in v4: > - Add Kconfig DELAY_DEVICE_PROBES to allow disabling delayed probing in > machines with initcalls that depend on devices probing at a given time. > > drivers/base/Kconfig | 18 ++++++++++++++++++ > drivers/base/dd.c | 6 ++++++ > include/linux/device.h | 2 ++ > 3 files changed, 26 insertions(+) > > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig > index 98504ec99c7d..8bb7b556da1b 100644 > --- a/drivers/base/Kconfig > +++ b/drivers/base/Kconfig > @@ -324,4 +324,22 @@ config CMA_ALIGNMENT > > endif > > +config DELAY_DEVICE_PROBES > + bool "Allow delaying the probe of some devices" if EXPERT > + default y > + help > + Devices can be matched to a driver and probed from the moment they > + are registered, but early during boot their probes are likely to be > + deferred because some dependency isn't available yet because most > + drivers haven't been registered yet. > + > + Enabling this option allows the device registration code to delay the > + probing of a specific device until device_initcall_sync, when all ^^^^^^^^^^^^^^^^^^^^ late_initcall > + built-in drivers have been registered already. > + > + In some platforms there may be implicit assumptions about when some > + devices are probed, so enabling this option could cause problems there. > + > + If unsure, say Y here. > + > endmenu > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > index 7dc04ee81c8b..c4a3f298e726 100644 > --- a/drivers/base/dd.c > +++ b/drivers/base/dd.c > @@ -417,6 +417,12 @@ int driver_probe_device(struct device_driver *drv, struct device *dev) > if (!device_is_registered(dev)) > return -ENODEV; > > + if (IS_ENABLED(CONFIG_DELAY_DEVICE_PROBES) && > + !driver_deferred_probe_enable && dev->probe_late) { > + driver_deferred_probe_add(dev); > + return 0; > + } > + > pr_debug("bus: '%s': %s: matched device %s with driver %s\n", > drv->bus->name, __func__, dev_name(dev), drv->name); > > diff --git a/include/linux/device.h b/include/linux/device.h > index 8e7b806f0744..e64f4c7e243d 100644 > --- a/include/linux/device.h > +++ b/include/linux/device.h > @@ -744,6 +744,7 @@ struct device_dma_parameters { > * > * @offline_disabled: If set, the device is permanently online. > * @offline: Set after successful invocation of bus type's .offline(). > + * @probe_late: If set, device will be probed in the late initcall level. > * > * At the lowest level, every device in a Linux system is represented by an > * instance of struct device. The device structure contains the information > @@ -828,6 +829,7 @@ struct device { > > bool offline_disabled:1; > bool offline:1; > + bool probe_late:1; > }; > > static inline struct device *kobj_to_dev(struct kobject *kobj) >
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig index 98504ec99c7d..8bb7b556da1b 100644 --- a/drivers/base/Kconfig +++ b/drivers/base/Kconfig @@ -324,4 +324,22 @@ config CMA_ALIGNMENT endif +config DELAY_DEVICE_PROBES + bool "Allow delaying the probe of some devices" if EXPERT + default y + help + Devices can be matched to a driver and probed from the moment they + are registered, but early during boot their probes are likely to be + deferred because some dependency isn't available yet because most + drivers haven't been registered yet. + + Enabling this option allows the device registration code to delay the + probing of a specific device until device_initcall_sync, when all + built-in drivers have been registered already. + + In some platforms there may be implicit assumptions about when some + devices are probed, so enabling this option could cause problems there. + + If unsure, say Y here. + endmenu diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 7dc04ee81c8b..c4a3f298e726 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -417,6 +417,12 @@ int driver_probe_device(struct device_driver *drv, struct device *dev) if (!device_is_registered(dev)) return -ENODEV; + if (IS_ENABLED(CONFIG_DELAY_DEVICE_PROBES) && + !driver_deferred_probe_enable && dev->probe_late) { + driver_deferred_probe_add(dev); + return 0; + } + pr_debug("bus: '%s': %s: matched device %s with driver %s\n", drv->bus->name, __func__, dev_name(dev), drv->name); diff --git a/include/linux/device.h b/include/linux/device.h index 8e7b806f0744..e64f4c7e243d 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -744,6 +744,7 @@ struct device_dma_parameters { * * @offline_disabled: If set, the device is permanently online. * @offline: Set after successful invocation of bus type's .offline(). + * @probe_late: If set, device will be probed in the late initcall level. * * At the lowest level, every device in a Linux system is represented by an * instance of struct device. The device structure contains the information @@ -828,6 +829,7 @@ struct device { bool offline_disabled:1; bool offline:1; + bool probe_late:1; }; static inline struct device *kobj_to_dev(struct kobject *kobj)
Add a field to struct device that instructs the device-driver core to defer the probe of this device until the late_initcall level. By letting all built-in drivers to register before starting to probe, we can avoid any deferred probes by probing dependencies on demand. Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> --- Changes in v7: - Move IS_ENABLED(CONFIG_DELAY_DEVICE_PROBES) into if condition - Hide CONFIG_DELAY_DEVICE_PROBES behind EXPERT Changes in v4: - Add Kconfig DELAY_DEVICE_PROBES to allow disabling delayed probing in machines with initcalls that depend on devices probing at a given time. drivers/base/Kconfig | 18 ++++++++++++++++++ drivers/base/dd.c | 6 ++++++ include/linux/device.h | 2 ++ 3 files changed, 26 insertions(+)