tty: Sort out the USB sysrq changes that wrecked performance
We can't go around calling all sorts of magic per character functions at
full rate 3G data speed.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 932d624..3d8dc56 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -424,10 +424,17 @@
if (!tty)
goto done;
- /* Push data to tty */
- for (i = 0; i < urb->actual_length; i++, ch++) {
- if (!usb_serial_handle_sysrq_char(port, *ch))
- tty_insert_flip_char(tty, *ch, TTY_NORMAL);
+ /* The per character mucking around with sysrq path it too slow for
+ stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
+ where the USB serial is not a console anyway */
+ if (!port->console || !port->sysrq)
+ tty_insert_flip_string(tty, ch, urb->actual_length);
+ else {
+ /* Push data to tty */
+ for (i = 0; i < urb->actual_length; i++, ch++) {
+ if (!usb_serial_handle_sysrq_char(port, *ch))
+ tty_insert_flip_char(tty, *ch, TTY_NORMAL);
+ }
}
tty_flip_buffer_push(tty);
tty_kref_put(tty);
