From 4cd1de0afaaa45309f34d7282ea4c07d9b56a3ff Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Thu, 9 Jul 2009 13:35:52 +0100 Subject: [PATCH] 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 Signed-off-by: Linus Torvalds --- drivers/usb/serial/generic.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c index 932d6241b787..3d8dc5671bea 100644 --- a/drivers/usb/serial/generic.c +++ b/drivers/usb/serial/generic.c @@ -424,10 +424,17 @@ static void flush_and_resubmit_read_urb(struct usb_serial_port *port) 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); -- 2.30.2