From: Alan Cox Date: Thu, 9 Jul 2009 12:35:52 +0000 (+0100) Subject: tty: Sort out the USB sysrq changes that wrecked performance X-Git-Tag: upstream/snapshot3+hdmi~18114 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4cd1de0afaaa45309f34d7282ea4c07d9b56a3ff;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git 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 --- 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 @@ 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);