From 95340d18e02c4edb5cebd2edb99f4b8b306bce24 Mon Sep 17 00:00:00 2001 From: riastradh Date: Sun, 17 Apr 2022 13:15:37 +0000 Subject: 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. --- sys/dev/usb/usb.h | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'sys/dev') diff --git a/sys/dev/usb/usb.h b/sys/dev/usb/usb.h index 2d0734433a4..92cf37d4ec4 100644 --- a/sys/dev/usb/usb.h +++ b/sys/dev/usb/usb.h @@ -1,4 +1,4 @@ -/* $NetBSD: usb.h,v 1.119 2021/10/11 00:25:05 jmcneill Exp $ */ +/* $NetBSD: usb.h,v 1.120 2022/04/17 13:15:37 riastradh Exp $ */ /* * Copyright (c) 1998 The NetBSD Foundation, Inc. @@ -202,12 +202,18 @@ typedef struct { #define USB_3_MAX_CTRL_PACKET 512 +/* + * This is the common header to all USB descriptors defined in the USB + * specification. + * + * DO NOT CHANGE THIS TYPE! + */ typedef struct { uByte bLength; uByte bDescriptorType; - uByte bDescriptorSubtype; } UPACKED usb_descriptor_t; -#define USB_DESCRIPTOR_SIZE 3 +#define USB_DESCRIPTOR_SIZE 2 +__CTASSERT(sizeof(usb_descriptor_t) == USB_DESCRIPTOR_SIZE); typedef struct { uByte bLength; -- cgit