diff options
Diffstat (limited to 'sys/dev/usb/usb.h')
| -rw-r--r-- | sys/dev/usb/usb.h | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/sys/dev/usb/usb.h b/sys/dev/usb/usb.h index ac1c866d202..78439b78b09 100644 --- a/sys/dev/usb/usb.h +++ b/sys/dev/usb/usb.h @@ -1,4 +1,4 @@ -/* $OpenBSD: usb.h,v 1.28 2007/06/17 07:53:11 mbalmer Exp $ */ +/* $OpenBSD: usb.h,v 1.29 2007/07/27 09:16:09 mbalmer Exp $ */ /* $NetBSD: usb.h,v 1.69 2002/09/22 23:20:50 augustss Exp $ */ /* $FreeBSD: src/sys/dev/usb/usb.h,v 1.14 1999/11/17 22:33:46 n_hibma Exp $ */ @@ -251,12 +251,21 @@ typedef struct { } __packed usb_endpoint_descriptor_t; #define USB_ENDPOINT_DESCRIPTOR_SIZE 7 +/* + * Note: The length of the USB string descriptor is stored in a one byte + * value and can therefore be no longer than 255 bytes. Two bytes are + * used for the length itself and the descriptor type, a theoretical maximum + * of 253 bytes is left for the actual string data. Since the strings are + * encoded as 2-byte unicode characters, only 252 bytes or 126 two-byte + * characters can be used. USB_MAX_STRING_LEN is defined as 127, leaving + * space for the terminal '\0' character in C strings. + */ typedef struct { uByte bLength; uByte bDescriptorType; - uWord bString[127]; + uWord bString[126]; } __packed usb_string_descriptor_t; -#define USB_MAX_STRING_LEN 128 +#define USB_MAX_STRING_LEN 127 #define USB_LANGUAGE_TABLE 0 /* # of the string language id table */ /* Hub specific request */ |