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authorTilman Schmidt <tilman@imap.cc>2015-07-14 01:37:13 +0300
committerDavid S. Miller <davem@davemloft.net>2015-07-16 03:24:45 +0300
commitfd98e9419d8d622a4de91f76b306af6aa627aa9c (patch)
treee9047d514d1ba80a6aad4027860dd1c4d4e3f42a /drivers/isdn
parent052cbda41fdc243a8d40cce7ab3a6327b4b2887e (diff)
downloadlinux-fd98e9419d8d622a4de91f76b306af6aa627aa9c.tar.xz
isdn/gigaset: reset tty->receive_room when attaching ser_gigaset
Commit 79901317ce80 ("n_tty: Don't flush buffer when closing ldisc"), first merged in kernel release 3.10, caused the following regression in the Gigaset M101 driver: Before that commit, when closing the N_TTY line discipline in preparation to switching to N_GIGASET_M101, receive_room would be reset to a non-zero value by the call to n_tty_flush_buffer() in n_tty's close method. With the removal of that call, receive_room might be left at zero, blocking data reception on the serial line. The present patch fixes that regression by setting receive_room to an appropriate value in the ldisc open method. Fixes: 79901317ce80 ("n_tty: Don't flush buffer when closing ldisc") Signed-off-by: Tilman Schmidt <tilman@imap.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/isdn')
-rw-r--r--drivers/isdn/gigaset/ser-gigaset.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/isdn/gigaset/ser-gigaset.c b/drivers/isdn/gigaset/ser-gigaset.c
index 8c91fd5eb6fd..3ac9c4194814 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
*/