Re: [PATCH v3 3/6] TTY: fix DTR being raised on hang up
From: Peter Hurley <hidden>
Date: 2013-03-15 11:58:08
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On Fri, 2013-03-15 at 12:30 +0100, Johan Hovold wrote:
On Fri, Mar 15, 2013 at 07:03:08AM -0400, Peter Hurley wrote:quoted
On Fri, 2013-03-15 at 10:24 +0100, Johan Hovold wrote:quoted
On Wed, Mar 13, 2013 at 03:43:43PM -0400, Peter Hurley wrote:quoted
On Thu, 2013-03-07 at 15:55 +0100, Johan Hovold wrote:quoted
Make sure to check ASYNC_INITIALISED before raising DTR when waking up from blocked open in tty_port_block_til_ready. Currently DTR could get raised at hang up as a blocked process would raise DTR unconditionally before checking for hang up and returning. Signed-off-by: Johan Hovold <redacted> --- drivers/tty/tty_port.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c index 3de5918..52f1066 100644 --- a/drivers/tty/tty_port.c +++ b/drivers/tty/tty_port.c@@ -355,7 +355,7 @@ int tty_port_block_til_ready(struct tty_port *port, while (1) { /* Indicate we are open */ - if (tty->termios.c_cflag & CBAUD) + if (C_BAUD(tty) && test_bit(ASYNCB_INITIALIZED, &port->flags)) tty_port_raise_dtr_rts(port); prepare_to_wait(&port->open_wait, &wait, TASK_INTERRUPTIBLE);This is ok, but there are 6 other *_block_til_ready() functions:^^^^^^ Comment on patchI saw that, but just wanted to stress that those comments shouldn't block the series.
I completely agree. In fact, I should have said as much in the initial review. Sorry.
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Yes, but that's not really a comment on this patch, is it? The purpose of this series is to fix the tty-port implementation, and I've only touched individual drivers when I had to in order not to break anything due to changed assumptions. There's a ton of buggy and odd behaviour to be found once you start turning the stones. Drivers like the ones below really ought to be using tty ports and it's helpers.Sure, I understand. OTOH, tty_port and these drivers stem from the same ancestor and it's partly because of localized bug fixes like these that the drivers have buggy and odd behavior (because tty_port gets fixed and these do not).Arguably, fixing the core isn't really a localised bug fix. Some of those drivers you mentioned have custom open, close, hangup which are quite different from the tty port implementation, and surely would have a lot to gain from being ported to tty ports if someone could find the time to do so.
I think the reluctance to do a full port is partly due to lack of testable hardware.
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As you can verify from the changelogs of these drivers, it's traditional to continue to maintain the common aspects, despite the desire to abandon them.Most entries I see have to do with changed interfaces.quoted
That said, I'm not the maintainer so feel free to disagree with my point-of-view.You do have a point, and I will try to find the time for a follow-up series fixing at least a few of those five-or-so custom block_til_ready you pointed to.
Thanks. Regards, Peter Hurley