W dniu 01.05.2014 03:36, Michal Nazarewicz pisze:
On Thu, Apr 24 2014, Andrzej Pietrasiewicz wrote:
There is a custom (non-USB IF) extension to the USB standard:
http://msdn.microsoft.com/library/windows/hardware/gg463182
<snip>
diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index fab9064..0bfdb14 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -960,6 +960,22 @@ static int get_string(struct usb_composite_dev *cdev,
return s->bLength;
}
+ if (cdev->use_os_string && language == 0 && id == OS_STRING_IDX) {
+ /*
+ * bLength|bDescriptorType|qwSignature|bMS_VendorCode|bPad
+ * ---------------------------------------------------------
+ * 1 Byte |1 Byte |14 Bytes |1 Byte |1 Byte
+ * ---------------------------------------------------------
+ */
It would be better to have a structure defined for this.
+ u8 *b = buf;
+ b[0] = 0x12;
+ b[1] = USB_DT_STRING;
+ memcpy(&b[2], cdev->qw_sign, OS_STRING_QW_SIGN_LEN);
+ b[2 + OS_STRING_QW_SIGN_LEN] = cdev->b_vendor_code;
+ b[3 + OS_STRING_QW_SIGN_LEN] = 0;
+ return 0x12;
+ }
+
The purpose of get_string() is to fill in the passed buf which is interpreted
as a string. The "OS String" is, indeed, a string ;)
Do I get it right that you suggest creating a struct and then memcpy'ing it
to the destination buffer?
Something on the lines of:
struct usb_os_string {
__u8 bLength;
__u8 bDescriptorType;
__u8 qwSignature[OS_STRING_QW_SIGN_LEN];
__u8 bMS_VendorCode;
__u8 bPad;
} __attribute__ ((packed));
And then have cdev have a struct usb_os_string member instead of
qw_sign and b_vendor_code?
AP
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