Hello,
The TIOCOUTQ ioctl calls chars_in_buffer(), and
some apps depend on a correct behaviour of that.
mos7840 implements it wrongly: if you write just
one char, TIOCOUTQ will return 32.
The attached patch should fix it.
But it is not tested: customer reported the problem
and fails to test the patch.
Please review.
https://bugzilla.kernel.org/show_bug.cgi?id=45791
Signed-off-by: Stas Sergeev <stsp@xxxxxxxxxxxxxxxxxxxxx>
From 02804e64f786d6aaaba54933f7cadd10dff2f497 Mon Sep 17 00:00:00 2001
From: Stas Sergeev <stsp@users.sourceforge.net>
Date: Mon, 23 Jul 2012 13:17:40 +0400
Subject: [PATCH] mos7840: fix chars_in_buffer
---
drivers/usb/serial/mos7840.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 57eca24..440d7f8 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -243,7 +243,7 @@ struct moschip_port {
spinlock_t pool_lock;
struct urb *write_urb_pool[NUM_URBS];
- char busy[NUM_URBS];
+ int busy[NUM_URBS];
bool read_urb_busy;
/* For device(s) with LED indicator */
@@ -1234,7 +1234,7 @@ static int mos7840_chars_in_buffer(struct tty_struct *tty)
spin_lock_irqsave(&mos7840_port->pool_lock, flags);
for (i = 0; i < NUM_URBS; ++i)
if (mos7840_port->busy[i])
- chars += URB_TRANSFER_BUFFER_SIZE;
+ chars += mos7840_port->busy[i];
spin_unlock_irqrestore(&mos7840_port->pool_lock, flags);
dbg("%s - returns %d", __func__, chars);
return chars;
@@ -1531,10 +1531,11 @@ static int mos7840_write(struct tty_struct *tty, struct usb_serial_port *port,
/* try to find a free urb in the list */
urb = NULL;
+ transfer_size = min(count, URB_TRANSFER_BUFFER_SIZE);
spin_lock_irqsave(&mos7840_port->pool_lock, flags);
for (i = 0; i < NUM_URBS; ++i) {
if (!mos7840_port->busy[i]) {
- mos7840_port->busy[i] = 1;
+ mos7840_port->busy[i] = transfer_size;
urb = mos7840_port->write_urb_pool[i];
dbg("URB:%d", i);
break;
@@ -1557,7 +1558,6 @@ static int mos7840_write(struct tty_struct *tty, struct usb_serial_port *port,
goto exit;
}
}
- transfer_size = min(count, URB_TRANSFER_BUFFER_SIZE);
memcpy(urb->transfer_buffer, current_position, transfer_size);
--
1.7.4.4
