From 36ba97fabbed2f2a4a89da5be221c630ea3ff66f Mon Sep 17 00:00:00 2001 From: Keith Packard Date: Thu, 9 Jun 2016 22:06:30 -0700 Subject: [PATCH] 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 --- src/stmf0/ao_usb_stm.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) 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); -- 2.30.2