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| author | Yinghai Lu <Yinghai.Lu@Sun.COM> | 2007-07-15 23:37:25 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-16 09:05:34 -0700 |
| commit | 79492689e40d4f4d3d8a7262781d56fb295b4b86 (patch) | |
| tree | f66255875725b87a986300735db7fe0212415695 /drivers | |
| parent | 23936cc0b5d89619c34c2dab11d8cf3d6f7ca028 (diff) | |
| download | kernel-common-79492689e40d4f4d3d8a7262781d56fb295b4b86.tar.gz kernel-common-79492689e40d4f4d3d8a7262781d56fb295b4b86.tar.bz2 kernel-common-79492689e40d4f4d3d8a7262781d56fb295b4b86.zip | |
serial: assert DTR for serial console devices
Some RS-232 devices require DTR to be asserted before they can be used. DTR
is normally asserted in uart_startup() when the port is opened. But we don't
actually open serial console ports, so assert DTR when the port is added.
BTW:
earlyprintk and early_uart are hard coded to set DTR/RTS.
rmk says
The only issue I can think of is the possibility for an attached modem to
auto-answer or maybe even auto-dial before the system is ready for it to do
so. Might have an undesirable cost implication for some running with such a
setup.
Apart from that, I can't think of any other side effect of this specific
patch.
Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Andi Kleen <ak@suse.de>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/serial/serial_core.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c index 326020f86f75..9c57486c2e7f 100644 --- a/drivers/serial/serial_core.c +++ b/drivers/serial/serial_core.c @@ -1910,6 +1910,12 @@ uart_set_options(struct uart_port *port, struct console *co, if (flow == 'r') termios.c_cflag |= CRTSCTS; + /* + * some uarts on other side don't support no flow control. + * So we set * DTR in host uart to make them happy + */ + port->mctrl |= TIOCM_DTR; + port->ops->set_termios(port, &termios, NULL); co->cflag = termios.c_cflag; |