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authorriastradh <riastradh@NetBSD.org>2022-04-17 13:15:37 +0000
committerriastradh <riastradh@NetBSD.org>2022-04-17 13:15:37 +0000
commit95340d18e02c4edb5cebd2edb99f4b8b306bce24 (patch)
tree74837cb1eab5a7d985fd30dd29f28933f61bc986 /sys/dev/usb
parent8f683709ef7e9a9ee77475bbe802953cc6173979 (diff)
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.
Diffstat (limited to 'sys/dev/usb')
-rw-r--r--sys/dev/usb/usb.h12
1 files changed, 9 insertions, 3 deletions
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;