n_gsm: Fix timings

Alek Du reported that the code erroneously applies time to jiffies
conversions twice to the t1 and t2 values. In normal use on a modem link
this cases no visible problem but on a slower link it will break as with
HZ=1000 as is typical we are running t1/t2 ten times too fast.

Alek's original patch removed the conversion from the timer setting but we
in fact have to be more careful as the contents of t1/t2 are visible via
the device API and we thus need to correct the constants.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 5 deletions

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 4cb0d0a3e57b..fc7bbba585ce 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -66,14 +66,16 @@
 static int debug;
 module_param(debug, int, 0600);
 
-#define T1      (HZ/10)
-#define T2      (HZ/3)
-#define N2      3
+/* Defaults: these are from the specification */
+
+#define T1      10              /* 100mS */
+#define T2      34              /* 333mS */
+#define N2      3               /* Retry 3 times */
 
 /* Use long timers for testing at low speed with debug on */
 #ifdef DEBUG_TIMING
-#define T1      HZ
-#define T2      (2 * HZ)
+#define T1      100
+#define T2      200
 #endif
 
 /*