diff mbox series

[v1] usb: core: fix pipe creation for get_bMaxPacketSize0

Message ID 20250203105840.17539-1-eichest@gmail.com
State New
Headers show
Series [v1] usb: core: fix pipe creation for get_bMaxPacketSize0 | expand

Commit Message

Stefan Eichenberger Feb. 3, 2025, 10:58 a.m. UTC 
From: Stefan Eichenberger <stefan.eichenberger@toradex.com>

When usb_control_msg is used in the get_bMaxPacketSize0 function, the
USB pipe does not include the endpoint device number. This can cause
failures when a usb hub port is reinitialized after encountering a bad
cable connection. As a result, the system logs the following error
messages:
usb usb2-port1: cannot reset (err = -32)
usb usb2-port1: Cannot enable. Maybe the USB cable is bad?
usb usb2-port1: attempt power cycle
usb 2-1: new high-speed USB device number 5 using ci_hdrc
usb 2-1: device descriptor read/8, error -71

The problem began after commit 85d07c556216 ("USB: core: Unite old
scheme and new scheme descriptor reads"). There
usb_get_device_descriptor was replaced with get_bMaxPacketSize0. Unlike
usb_get_device_descriptor, the get_bMaxPacketSize0 function uses the
macro usb_rcvaddr0pipe, which does not include the endpoint device
number. usb_get_device_descriptor, on the other hand, used the macro
usb_rcvctrlpipe, which includes the endpoint device number.

By modifying the get_bMaxPacketSize0 function to use usb_rcvctrlpipe
instead of usb_rcvaddr0pipe, the issue can be resolved. This change will
ensure that the endpoint device number is included in the USB pipe,
preventing reinitialization failures. If the endpoint has not set the
device number yet, it will still work because the device number is 0 in
udev.

Cc: stable@vger.kernel.org
Fixes: 85d07c556216 ("USB: core: Unite old scheme and new scheme descriptor reads")
Signed-off-by: Stefan Eichenberger <stefan.eichenberger@toradex.com>
---
Before commit  85d07c556216 ("USB: core: Unite old scheme and new scheme
descriptor reads") usb_rcvaddr0pipe was used in hub_port_init. With this
proposed change, usb_rcvctrlpipe will be used which includes devnum for
the pipe. I'm not sure if this might have some side effects. However, my
understanding is that devnum is set to the right value (might also be 0
if not initialised) before get_bMaxPacketSize0 is called. Therefore,
this should work but please let me know if I'm wrong on this.
---
 drivers/usb/core/hub.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index c3f839637cb5..59e38780f76d 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -4698,7 +4698,6 @@  void usb_ep0_reinit(struct usb_device *udev)
 EXPORT_SYMBOL_GPL(usb_ep0_reinit);
 
 #define usb_sndaddr0pipe()	(PIPE_CONTROL << 30)
-#define usb_rcvaddr0pipe()	((PIPE_CONTROL << 30) | USB_DIR_IN)
 
 static int hub_set_address(struct usb_device *udev, int devnum)
 {
@@ -4804,7 +4803,7 @@  static int get_bMaxPacketSize0(struct usb_device *udev,
 	for (i = 0; i < GET_MAXPACKET0_TRIES; ++i) {
 		/* Start with invalid values in case the transfer fails */
 		buf->bDescriptorType = buf->bMaxPacketSize0 = 0;
-		rc = usb_control_msg(udev, usb_rcvaddr0pipe(),
+		rc = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
 				USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
 				USB_DT_DEVICE << 8, 0,
 				buf, size,