---
- branch: MAIN
  date: Sun Apr 17 13:15:37 UTC 2022
  files:
  - new: '1.120'
    old: '1.119'
    path: src/sys/dev/usb/usb.h
    pathrev: src/sys/dev/usb/usb.h@1.120
    type: modified
  id: 20220417T131537Z.c6cf1ffc59a84b174a0c637fc056977710852493
  log: |
    usbdi(9): Restore usb_descriptor_t to its correct definition.

    Descriptors in the USB spec all start with bLength and
    bDescriptorType.  bDescriptorSubtype is only for certain
    class-specific descriptors.  Many descriptors, such as
    usb_device_descriptor_t, _do not_ have bDescriptorSubtype, so using a
    structure that has bDescriptorSubtype for such descrpitors is wrong.

    There is some history here:

    - Back in 1998, when augustss@ introduced the USB stack, the type
      usb_descriptor_t was erroneously defined with a bDescriptorSubtype
      member.

    - In 2007, drochner@ removed this member to accurately reflect the
      USB spec.

    - In 2018, khorben@ appeared to have accidentally reintroduced it
      while importing the umb(4) driver from OpenBSD, which still has the
      erroneous bDescriptorSubtype member in usb_descriptor_t.

    The umb(4) driver has since been adjusted to correctly use
    usb_cdc_descriptor_t instead of usb_descriptor_t (and I have now
    restored umidi_cs_descriptor_t which I had removed last month before
    I realized this history of usb_descriptor_t), so this member is no
    longer necessary.
  module: src
  subject: 'CVS commit: src/sys/dev/usb'
  unixtime: '1650201337'
  user: riastradh