svn commit: r342724 - stable/10/sys/dev/sound/usb

[Hans Petter Selasky]

Author: hselasky
Date: Thu Jan  3 09:25:39 2019
New Revision: 342724
URL: https://svnweb.freebsd.org/changeset/base/342724

Log:
  MFC r342456:
  Fix reading of USB sample rate descriptor for SPL Crimson Rev 1.
  
  Read first one entry, then try to read the full rate descriptor table.
  
  PR:			234380
  Sponsored by:		Mellanox Technologies

Modified:
  stable/10/sys/dev/sound/usb/uaudio.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/dev/sound/usb/uaudio.c
==============================================================================
--- stable/10/sys/dev/sound/usb/uaudio.c	Thu Jan  3 09:24:37 2019	(r342723)
+++ stable/10/sys/dev/sound/usb/uaudio.c	Thu Jan  3 09:25:39 2019	(r342724)
@@ -1524,7 +1524,8 @@ uaudio20_check_rate(struct usb_device *udev, uint8_t i
 {
 	struct usb_device_request req;
 	usb_error_t error;
-	uint8_t data[255];
+#define	UAUDIO20_MAX_RATES 32	/* we support at maxium 32 rates */
+	uint8_t data[2 + UAUDIO20_MAX_RATES * 12];
 	uint16_t actlen;
 	uint16_t rates;
 	uint16_t x;
@@ -1536,19 +1537,57 @@ uaudio20_check_rate(struct usb_device *udev, uint8_t i
 	req.bRequest = UA20_CS_RANGE;
 	USETW2(req.wValue, UA20_CS_SAM_FREQ_CONTROL, 0);
 	USETW2(req.wIndex, clockid, iface_no);
-	USETW(req.wLength, 255);
+	/*
+	 * Assume there is at least one rate to begin with, else some
+	 * devices might refuse to return the USB descriptor:
+	 */
+	USETW(req.wLength, (2 + 1 * 12));
 
-        error = usbd_do_request_flags(udev, NULL, &req, data,
+	error = usbd_do_request_flags(udev, NULL, &req, data,
 	    USB_SHORT_XFER_OK, &actlen, USB_DEFAULT_TIMEOUT);
 
-	if (error != 0 || actlen < 2)
-		return (USB_ERR_INVAL);
+	if (error != 0 || actlen < 2) {
+		/*
+		 * Likely the descriptor doesn't fit into the supplied
+		 * buffer. Try using a larger buffer and see if that
+		 * helps:
+		 */
+		rates = MIN(UAUDIO20_MAX_RATES, (255 - 2) / 12);
+		error = USB_ERR_INVAL;
+	} else {
+		rates = UGETW(data);
 
-	rates = data[0] | (data[1] << 8);
+		if (rates > UAUDIO20_MAX_RATES) {
+			DPRINTF("Too many rates truncating to %d\n", UAUDIO20_MAX_RATES);
+			rates = UAUDIO20_MAX_RATES;
+			error = USB_ERR_INVAL;
+		} else if (rates > 1) {
+			DPRINTF("Need to read full rate descriptor\n");
+			error = USB_ERR_INVAL;
+		}
+	}
+
+	if (error != 0) {
+		/*
+		 * Try to read full rate descriptor.
+		 */
+		actlen = (2 + rates * 12);
+
+		USETW(req.wLength, actlen);
+
+	        error = usbd_do_request_flags(udev, NULL, &req, data,
+		    USB_SHORT_XFER_OK, &actlen, USB_DEFAULT_TIMEOUT);
+	
+		if (error != 0 || actlen < 2)
+			return (USB_ERR_INVAL);
+
+		rates = UGETW(data);
+	}
+
 	actlen = (actlen - 2) / 12;
 
 	if (rates > actlen) {
-		DPRINTF("Too many rates\n");
+		DPRINTF("Too many rates truncating to %d\n", actlen);
 		rates = actlen;
 	}