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| author | Breno Leitao <leitao@debian.org> | 2026-08-05 07:52:36 -0700 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2026-08-10 11:47:20 -1000 |
| commit | a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656 (patch) | |
| tree | 39f5b258386e1127d253d293194e9a2991bf3c34 /Documentation/usb/functionfs-desc.rst | |
| download | linux-stable-a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656.tar.gz linux-stable-a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656.zip | |
workqueue: skip the node_nr_active update for non-unbound workqueuesgrafted
apply_wqattrs_commit() updates node_nr_active->max unconditionally.
wq->node_nr_active[] is only allocated for unbound workqueues, so guard
the call before per-cpu workqueues start using this path.
No functional change: only unbound workqueues reach apply_wqattrs_*()
today.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'Documentation/usb/functionfs-desc.rst')
| -rw-r--r-- | Documentation/usb/functionfs-desc.rst | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/Documentation/usb/functionfs-desc.rst b/Documentation/usb/functionfs-desc.rst new file mode 100644 index 000000000..39649774d --- /dev/null +++ b/Documentation/usb/functionfs-desc.rst @@ -0,0 +1,39 @@ +====================== +FunctionFS Descriptors +====================== + +Some of the descriptors that can be written to the FFS gadget are +described below. Device and configuration descriptors are handled +by the composite gadget and are not written by the user to the +FFS gadget. + +Descriptors are written to the "ep0" file in the FFS gadget +following the descriptor header. + +.. kernel-doc:: include/uapi/linux/usb/functionfs.h + :doc: descriptors + +Interface Descriptors +--------------------- + +Standard USB interface descriptors may be written. The class/subclass of the +most recent interface descriptor determines what type of class-specific +descriptors are accepted. + +Class-Specific Descriptors +-------------------------- + +Class-specific descriptors are accepted only for the class/subclass of the +most recent interface descriptor. The following are some of the +class-specific descriptors that are supported. + +DFU Functional Descriptor +~~~~~~~~~~~~~~~~~~~~~~~~~ + +When the interface class is USB_CLASS_APP_SPEC and the interface subclass +is USB_SUBCLASS_DFU, a DFU functional descriptor can be provided. +The DFU functional descriptor is a described in the USB specification for +Device Firmware Upgrade (DFU), version 1.1 as of this writing. + +.. kernel-doc:: include/uapi/linux/usb/functionfs.h + :doc: usb_dfu_functional_descriptor |
