Re: [REGRESSION] "USB: use kfifo to buffer usb-generic serial writes" causes gobi_loader to hang

[Oliver Neukum <oliver@neukum.org>]

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Am Montag, 18. Januar 2010 02:58:44 schrieb Matthew Garrett:
> drivers/usb/serial/generic.c: usb_serial_generic_write - port 0
> drivers/usb/serial/usb-serial.c: serial_write - port 0, 1536 byte(s)
> drivers/usb/serial/generic.c: usb_serial_generic_write - port 0
> drivers/usb/serial/usb-serial.c: usb_serial_port_work - port 0
> drivers/usb/serial/usb-serial.c: serial_write - port 0, 1536 byte(s)
> drivers/usb/serial/generic.c: usb_serial_generic_write - port 0

Hi,

it is not conclusive. Can you apply the attached patch and try again?

	Regards
		Oliver

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From 27e54a5d36aba23276d30bd61b962916dca7a946 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oliver@neukum.org>
Date: Mon, 18 Jan 2010 18:23:09 +0100
Subject: [PATCH] additional debugging

---
 drivers/usb/serial/generic.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index f1ea3a3..76e5514 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -283,6 +283,8 @@ static int usb_serial_generic_write_start(struct usb_serial_port *port)
 
 	if (!start_io)
 		return 0;
+	
+	dbg("%s - starting IO", __func__);
 
 	data = port->write_urb->transfer_buffer;
 	count = kfifo_out_locked(&port->write_fifo, data, port->bulk_out_size, &port->lock);
@@ -330,7 +332,7 @@ int usb_serial_generic_write(struct tty_struct *tty,
 	struct usb_serial *serial = port->serial;
 	int result;
 
-	dbg("%s - port %d", __func__, port->number);
+	dbg("%s - port %d, %d bytes", __func__, port->number, count);
 
 	if (count == 0) {
 		dbg("%s - write request of 0 bytes", __func__);
@@ -346,6 +348,7 @@ int usb_serial_generic_write(struct tty_struct *tty,
 						  buf, count);
 
 	count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
+	dbg("%s - put %d bytes into fifo", __func__, count);
 	result = usb_serial_generic_write_start(port);
 
 	if (result >= 0)
-- 
1.6.4.2