Loading Documentation/admin-guide/kernel-parameters.rst +1 −0 Original line number Diff line number Diff line Loading @@ -127,6 +127,7 @@ parameter is applicable:: NET Appropriate network support is enabled. NUMA NUMA support is enabled. NFS Appropriate NFS support is enabled. OF Devicetree is enabled. OSS OSS sound support is enabled. PV_OPS A paravirtualized kernel is enabled. PARIDE The ParIDE (parallel port IDE) subsystem is enabled. Loading Documentation/admin-guide/kernel-parameters.txt +6 −0 Original line number Diff line number Diff line Loading @@ -3194,6 +3194,12 @@ This can be set from sysctl after boot. See Documentation/admin-guide/sysctl/vm.rst for details. of_devlink [OF, KNL] Create device links between consumer and supplier devices by scanning the devictree to infer the consumer/supplier relationships. A consumer device will not be probed until all the supplier devices have probed successfully. ohci1394_dma=early [HW] enable debugging via the ohci1394 driver. See Documentation/debugging-via-ohci1394.txt for more info. Loading Documentation/driver-api/device_link.rst +2 −1 Original line number Diff line number Diff line Loading @@ -281,7 +281,8 @@ State machine :c:func:`driver_bound()`.) * Before a consumer device is probed, presence of supplier drivers is verified by checking that links to suppliers are in ``DL_STATE_AVAILABLE`` verified by checking the consumer device is not in the wait_for_suppliers list and by checking that links to suppliers are in ``DL_STATE_AVAILABLE`` state. The state of the links is updated to ``DL_STATE_CONSUMER_PROBE``. (Call to :c:func:`device_links_check_suppliers()` from :c:func:`really_probe()`.) Loading Documentation/driver-api/driver-model/devres.rst +4 −0 Original line number Diff line number Diff line Loading @@ -316,6 +316,10 @@ IOMAP devm_ioremap_nocache() devm_ioremap_wc() devm_ioremap_resource() : checks resource, requests memory region, ioremaps devm_ioremap_resource_wc() devm_platform_ioremap_resource() : calls devm_ioremap_resource() for platform device devm_platform_ioremap_resource_wc() devm_platform_ioremap_resource_byname() devm_iounmap() pcim_iomap() pcim_iomap_regions() : do request_region() and iomap() on multiple BARs Loading Documentation/driver-api/driver-model/driver.rst +43 −0 Original line number Diff line number Diff line Loading @@ -169,6 +169,49 @@ A driver's probe() may return a negative errno value to indicate that the driver did not bind to this device, in which case it should have released all resources it allocated:: void (*sync_state)(struct device *dev); sync_state is called only once for a device. It's called when all the consumer devices of the device have successfully probed. The list of consumers of the device is obtained by looking at the device links connecting that device to its consumer devices. The first attempt to call sync_state() is made during late_initcall_sync() to give firmware and drivers time to link devices to each other. During the first attempt at calling sync_state(), if all the consumers of the device at that point in time have already probed successfully, sync_state() is called right away. If there are no consumers of the device during the first attempt, that too is considered as "all consumers of the device have probed" and sync_state() is called right away. If during the first attempt at calling sync_state() for a device, there are still consumers that haven't probed successfully, the sync_state() call is postponed and reattempted in the future only when one or more consumers of the device probe successfully. If during the reattempt, the driver core finds that there are one or more consumers of the device that haven't probed yet, then sync_state() call is postponed again. A typical use case for sync_state() is to have the kernel cleanly take over management of devices from the bootloader. For example, if a device is left on and at a particular hardware configuration by the bootloader, the device's driver might need to keep the device in the boot configuration until all the consumers of the device have probed. Once all the consumers of the device have probed, the device's driver can synchronize the hardware state of the device to match the aggregated software state requested by all the consumers. Hence the name sync_state(). While obvious examples of resources that can benefit from sync_state() include resources such as regulator, sync_state() can also be useful for complex resources like IOMMUs. For example, IOMMUs with multiple consumers (devices whose addresses are remapped by the IOMMU) might need to keep their mappings fixed at (or additive to) the boot configuration until all its consumers have probed. While the typical use case for sync_state() is to have the kernel cleanly take over management of devices from the bootloader, the usage of sync_state() is not restricted to that. Use it whenever it makes sense to take an action after all the consumers of a device have probed. int (*remove) (struct device *dev); remove is called to unbind a driver from a device. This may be Loading Loading
Documentation/admin-guide/kernel-parameters.rst +1 −0 Original line number Diff line number Diff line Loading @@ -127,6 +127,7 @@ parameter is applicable:: NET Appropriate network support is enabled. NUMA NUMA support is enabled. NFS Appropriate NFS support is enabled. OF Devicetree is enabled. OSS OSS sound support is enabled. PV_OPS A paravirtualized kernel is enabled. PARIDE The ParIDE (parallel port IDE) subsystem is enabled. Loading
Documentation/admin-guide/kernel-parameters.txt +6 −0 Original line number Diff line number Diff line Loading @@ -3194,6 +3194,12 @@ This can be set from sysctl after boot. See Documentation/admin-guide/sysctl/vm.rst for details. of_devlink [OF, KNL] Create device links between consumer and supplier devices by scanning the devictree to infer the consumer/supplier relationships. A consumer device will not be probed until all the supplier devices have probed successfully. ohci1394_dma=early [HW] enable debugging via the ohci1394 driver. See Documentation/debugging-via-ohci1394.txt for more info. Loading
Documentation/driver-api/device_link.rst +2 −1 Original line number Diff line number Diff line Loading @@ -281,7 +281,8 @@ State machine :c:func:`driver_bound()`.) * Before a consumer device is probed, presence of supplier drivers is verified by checking that links to suppliers are in ``DL_STATE_AVAILABLE`` verified by checking the consumer device is not in the wait_for_suppliers list and by checking that links to suppliers are in ``DL_STATE_AVAILABLE`` state. The state of the links is updated to ``DL_STATE_CONSUMER_PROBE``. (Call to :c:func:`device_links_check_suppliers()` from :c:func:`really_probe()`.) Loading
Documentation/driver-api/driver-model/devres.rst +4 −0 Original line number Diff line number Diff line Loading @@ -316,6 +316,10 @@ IOMAP devm_ioremap_nocache() devm_ioremap_wc() devm_ioremap_resource() : checks resource, requests memory region, ioremaps devm_ioremap_resource_wc() devm_platform_ioremap_resource() : calls devm_ioremap_resource() for platform device devm_platform_ioremap_resource_wc() devm_platform_ioremap_resource_byname() devm_iounmap() pcim_iomap() pcim_iomap_regions() : do request_region() and iomap() on multiple BARs Loading
Documentation/driver-api/driver-model/driver.rst +43 −0 Original line number Diff line number Diff line Loading @@ -169,6 +169,49 @@ A driver's probe() may return a negative errno value to indicate that the driver did not bind to this device, in which case it should have released all resources it allocated:: void (*sync_state)(struct device *dev); sync_state is called only once for a device. It's called when all the consumer devices of the device have successfully probed. The list of consumers of the device is obtained by looking at the device links connecting that device to its consumer devices. The first attempt to call sync_state() is made during late_initcall_sync() to give firmware and drivers time to link devices to each other. During the first attempt at calling sync_state(), if all the consumers of the device at that point in time have already probed successfully, sync_state() is called right away. If there are no consumers of the device during the first attempt, that too is considered as "all consumers of the device have probed" and sync_state() is called right away. If during the first attempt at calling sync_state() for a device, there are still consumers that haven't probed successfully, the sync_state() call is postponed and reattempted in the future only when one or more consumers of the device probe successfully. If during the reattempt, the driver core finds that there are one or more consumers of the device that haven't probed yet, then sync_state() call is postponed again. A typical use case for sync_state() is to have the kernel cleanly take over management of devices from the bootloader. For example, if a device is left on and at a particular hardware configuration by the bootloader, the device's driver might need to keep the device in the boot configuration until all the consumers of the device have probed. Once all the consumers of the device have probed, the device's driver can synchronize the hardware state of the device to match the aggregated software state requested by all the consumers. Hence the name sync_state(). While obvious examples of resources that can benefit from sync_state() include resources such as regulator, sync_state() can also be useful for complex resources like IOMMUs. For example, IOMMUs with multiple consumers (devices whose addresses are remapped by the IOMMU) might need to keep their mappings fixed at (or additive to) the boot configuration until all its consumers have probed. While the typical use case for sync_state() is to have the kernel cleanly take over management of devices from the bootloader, the usage of sync_state() is not restricted to that. Use it whenever it makes sense to take an action after all the consumers of a device have probed. int (*remove) (struct device *dev); remove is called to unbind a driver from a device. This may be Loading
