USB: cypress_m8: allow unstable baud rates

I've got a crappy cypress converter here, and while running at higher
baud rates craps out on throughput, it works fine with lower ones.
While it'd be nice to simply use a lower baud rate, not all devices
can be configured this way, and it is possible to (slowly) interact
at higher rates by sending a byte at a time.  So let people force
higher rates when they need it via a module parameter.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index 47a18193abad..60c200230bc8 100644
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -73,6 +73,7 @@
 static int debug;
 static int stats;
 static int interval;
+static int unstable_bauds;
 
 /*
  * Version Information
@@ -291,6 +292,9 @@ static int analyze_baud_rate(struct usb_serial_port *port, speed_t new_rate)
         struct cypress_private *priv;
         priv = usb_get_serial_port_data(port);
 
+        if (unstable_bauds)
+                return new_rate;
+
         /*
          * The general purpose firmware for the Cypress M8 allows for
          * a maximum speed of 57600bps (I have no idea whether DeLorme
@@ -1643,3 +1647,5 @@ module_param(stats, bool, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(stats, "Enable statistics or not");
 module_param(interval, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(interval, "Overrides interrupt interval");
+module_param(unstable_bauds, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(unstable_bauds, "Allow unstable baud rates");