From: Keith Packard <keithp@keithp.com>
Date: Fri, 10 Jun 2016 05:06:30 +0000 (-0700)
Subject: stmf0: Do not send more data than requested for GET_DESCRIPTOR
X-Git-Tag: 1.6.4~1^2~24
X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=36ba97fabbed2f2a4a89da5be221c630ea3ff66f

stmf0: Do not send more data than requested for GET_DESCRIPTOR

When Linux boots, it asks for only the first 8 bytes of the device
descriptor; we must limit the amount of data sent back to that amount
or USB will get wedged.

Signed-off-by: Keith Packard <keithp@keithp.com>
---

diff --git a/src/stmf0/ao_usb_stm.c b/src/stmf0/ao_usb_stm.c
index a67fc868..63b35b24 100644
--- a/src/stmf0/ao_usb_stm.c
+++ b/src/stmf0/ao_usb_stm.c
@@ -683,7 +683,7 @@ ao_usb_serial_init(void)
 /* Walk through the list of descriptors and find a match
  */
 static void
-ao_usb_get_descriptor(uint16_t value)
+ao_usb_get_descriptor(uint16_t value, uint16_t length)
 {
 	const uint8_t		*descriptor;
 	uint8_t		type = value >> 8;
@@ -704,6 +704,8 @@ ao_usb_get_descriptor(uint16_t value)
 				len = sizeof (ao_usb_serial);
 			}
 #endif
+			if (len > length)
+				len = length;
 			ao_usb_ep0_in_set(descriptor, len);
 			break;
 		}
@@ -748,7 +750,7 @@ ao_usb_ep0_setup(void)
 				break;
 			case AO_USB_REQ_GET_DESCRIPTOR:
 				debug ("get descriptor %d\n", ao_usb_setup.value);
-				ao_usb_get_descriptor(ao_usb_setup.value);
+				ao_usb_get_descriptor(ao_usb_setup.value, ao_usb_setup.length);
 				break;
 			case AO_USB_REQ_GET_CONFIGURATION:
 				debug ("get configuration %d\n", ao_usb_configuration);