Merge branch 'isdn-gigaset-fixes'

Tilman Schmidt says:

====================
Fix long-standing regression in ser_gigaset ISDN driver

This series fixes a serious regression in the Gigaset M101 driver
introduced in kernel release 3.10 and removes some unneeded code.

Please also queue up patch 1 of the series for inclusion in the
stable/longterm releases 3.10 and later.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 25 deletions

diff --git a/drivers/isdn/gigaset/ser-gigaset.c b/drivers/isdn/gigaset/ser-gigaset.c
index 8c91fd5eb6fd..375be509e95f 100644
--- a/drivers/isdn/gigaset/ser-gigaset.c
+++ b/drivers/isdn/gigaset/ser-gigaset.c
@@ -524,9 +524,18 @@ gigaset_tty_open(struct tty_struct *tty)
         cs->hw.ser->tty = tty;
         atomic_set(&cs->hw.ser->refcnt, 1);
         init_completion(&cs->hw.ser->dead_cmp);
-
         tty->disc_data = cs;
 
+        /* Set the amount of data we're willing to receive per call
+         * from the hardware driver to half of the input buffer size
+         * to leave some reserve.
+         * Note: We don't do flow control towards the hardware driver.
+         * If more data is received than will fit into the input buffer,
+         * it will be dropped and an error will be logged. This should
+         * never happen as the device is slow and the buffer size ample.
+         */
+        tty->receive_room = RBUFSIZE/2;
+
         /* OK.. Initialization of the datastructures and the HW is done.. Now
          * startup system and notify the LL that we are ready to run
          */
@@ -598,28 +607,6 @@ static int gigaset_tty_hangup(struct tty_struct *tty)
 }
 
 /*
- * Read on the tty.
- * Unused, received data goes only to the Gigaset driver.
- */
-static ssize_t
-gigaset_tty_read(struct tty_struct *tty, struct file *file,
-                 unsigned char __user *buf, size_t count)
-{
-        return -EAGAIN;
-}
-
-/*
- * Write on the tty.
- * Unused, transmit data comes only from the Gigaset driver.
- */
-static ssize_t
-gigaset_tty_write(struct tty_struct *tty, struct file *file,
-                  const unsigned char *buf, size_t count)
-{
-        return -EAGAIN;
-}
-
-/*
  * Ioctl on the tty.
  * Called in process context only.
  * May be re-entered by multiple ioctl calling threads.
@@ -752,8 +739,6 @@ static struct tty_ldisc_ops gigaset_ldisc = {
         .open           = gigaset_tty_open,
         .close          = gigaset_tty_close,
         .hangup         = gigaset_tty_hangup,
-        .read           = gigaset_tty_read,
-        .write          = gigaset_tty_write,
         .ioctl          = gigaset_tty_ioctl,
         .receive_buf    = gigaset_tty_receive,
         .write_wakeup   = gigaset_tty_wakeup,