src/sys/dev/usb/usb_request.c, branch release/12.3.0

MFC r368659 and r368664:

2020-12-28T13:04:56Z

Improve handling of alternate settings in the USB stack. Allow setting the alternate interface number to fail when there is only one alternate setting present, to comply with the USB specification. Refactor how iface->num_altsetting is computed. Bump the __FreeBSD_version due to change of core USB structure. PR: 251856 Submitted by: Ma, Horse Sponsored by: Mellanox Technologies // NVIDIA Networking

MFC r366536:

2020-10-20T08:33:11Z

Try a bit harder to get the USB device descriptor in case the initial read fails. Sponsored by: Mellanox Technologies // NVIDIA Networking

MFC r364932:

2020-09-21T18:27:44Z

Allow slow USB devices to be given more time to return their USB descriptors, like Logitech HD Pro Webcam C920. PR: 248926 Sponsored by: Mellanox Technologies

MFC r342778:

2019-01-18T08:47:48Z

Reduce timeout for reading the USB HUB port status to 1000ms and try to filter out dead USB HUB devices by implementing an error counter, so that the USB enumeration thread does not spend all its time reading from non-responding devices, blocking user-space access in the end. Tested by: Matthias Apitz Sponsored by: Mellanox Technologies

Improve the kernel's USB descriptor reading function.

2018-06-27T12:08:12Z

Some USB devices does not allow a partial descriptor readout. Found by: bz@ MFC after: 1 week Sponsored by: Mellanox Technologies

Permit "(", ")", ":", and "/" in USB string descriptors.

2018-05-19T10:49:51Z

This way we can properly show descriptors with URLs in them. Reviewed by: hselasky@ MFC after: 2 weeks Sponsored by: The FreeBSD Foundation

sys/dev: further adoption of SPDX licensing ID tags.

2017-11-27T14:52:40Z

Mainly focus on files that use BSD 2-Clause license, however the tool I was using misidentified many licenses so this was mostly a manual - error prone - task. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts.

Improve USB polling mode by not locking any mutexes, asserting any

2016-09-14T12:07:34Z

mutexes or using any callouts when active. Trying to lock a mutex when KDB is active or the scheduler is stopped can result in infinite wait loops. The same goes for calling callout related functions which in turn lock mutexes. If the USB controller at which a USB keyboard is connected is idle when KDB is entered, polling the USB keyboard via USB will always succeed. Else polling may fail depending on which state the USB subsystem and USB interrupt handler is in. This is unavoidable unless KDB can wait for USB interrupt threads to complete before stalling the CPU(s). Tested by: Bruce Evans MFC after: 4 weeks

Resolve deadlock between device_detach() and usbd_do_request_flags()

2016-09-05T15:35:58Z

by reviving the SX control request lock and refining which lock protects the common scratch area in "struct usb_device". The SX control request lock was removed by r246759 because it caused a lock order reversal with the USB enumeration lock inside usbd_transfer_setup() as a function of r246616. It was thought that reducing the number of locks would resolve the LOR, but because some USB device drivers use usbd_do_request_flags() inside callback functions, like in taskqueues, a deadlock may occur when these are drained from device_detach(). By restoring the SX control request lock usbd_do_request_flags() is allowed to complete its execution when a USB device driver is detaching. By using the SX control request lock to protect the scratch area, the LOR introduced by r246616 is also resolved. Bump the FreeBSD version while at it to force recompilation of all USB kernel modules. Found by: avos@ MFC after: 1 week

Make a bunch of USB debug SYSCTLs tunable, so that their value(s) can

2015-01-05T15:04:17Z

be set before the USB device(s) are probed.