From: Benjamin Herrenschmidt <benh@au1.ibm.com>
To: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: linux-s390@vger.kernel.org, gregkh@linuxfoundation.org,
heiko.carstens@de.ibm.com, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org, brueckner@linux.vnet.com,
schwidefsky@de.ibm.com, jslaby@suse.cz
Subject: Re: [PATCH 1/2] tty/hvc_console: Add DTR/RTS callback to handle HUPCL control
Date: Wed, 16 Oct 2013 18:21:12 -0500 [thread overview]
Message-ID: <1381965672.17841.71.camel@pasglop> (raw)
In-Reply-To: <20131016090432.GA6053@linux.vnet.ibm.com>
On Wed, 2013-10-16 at 11:04 +0200, Hendrik Brueckner wrote:
> Indeed, two callbacks change the DTR line. The main difference is that
> tiocmget/tiocmset can be called from user space by ioctl. That's not the case
> for the dtr_cts callback. Also, tiocmget/tiocmset provide more flags that can
> be changed (ST, SR, CTS, CD, RNG, RI, ...)
>
> Assume we would like to unify them have a single callback to change DTR, then
> we have to take care of these differences. So the question to you now is
> whether you plan for a) other modem flags to be changed and b) if changing the
> DTR line (or other control flags) through an ioctl?
>
> Depending on your results, I could work on sth that helps us both and reduces
> the callbacks.
Can we not just have the users of dtr_cts just call the backend's tiocmset ?
If they need to filter or clamp bits, we could handle all that in hvc_console
by caching the user intended value and passing a cooked value down to the backend..
None of that is urgent or anything, it's just odd and would be nice to cleanup.
Cheers,
Ben.
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@au1.ibm.com>
To: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: jslaby@suse.cz, gregkh@linuxfoundation.org,
brueckner@linux.vnet.com, heiko.carstens@de.ibm.com,
schwidefsky@de.ibm.com, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org
Subject: Re: [PATCH 1/2] tty/hvc_console: Add DTR/RTS callback to handle HUPCL control
Date: Wed, 16 Oct 2013 18:21:12 -0500 [thread overview]
Message-ID: <1381965672.17841.71.camel@pasglop> (raw)
In-Reply-To: <20131016090432.GA6053@linux.vnet.ibm.com>
On Wed, 2013-10-16 at 11:04 +0200, Hendrik Brueckner wrote:
> Indeed, two callbacks change the DTR line. The main difference is that
> tiocmget/tiocmset can be called from user space by ioctl. That's not the case
> for the dtr_cts callback. Also, tiocmget/tiocmset provide more flags that can
> be changed (ST, SR, CTS, CD, RNG, RI, ...)
>
> Assume we would like to unify them have a single callback to change DTR, then
> we have to take care of these differences. So the question to you now is
> whether you plan for a) other modem flags to be changed and b) if changing the
> DTR line (or other control flags) through an ioctl?
>
> Depending on your results, I could work on sth that helps us both and reduces
> the callbacks.
Can we not just have the users of dtr_cts just call the backend's tiocmset ?
If they need to filter or clamp bits, we could handle all that in hvc_console
by caching the user intended value and passing a cooked value down to the backend..
None of that is urgent or anything, it's just odd and would be nice to cleanup.
Cheers,
Ben.
next prev parent reply other threads:[~2013-10-16 23:21 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-02 15:07 [PATCH 0/2] hvc_console: Add DTR/RTS callbacks to handle HUPCL conditions Hendrik Brueckner
2013-07-02 15:07 ` Hendrik Brueckner
2013-07-02 15:07 ` [PATCH 1/2] tty/hvc_console: Add DTR/RTS callback to handle HUPCL control Hendrik Brueckner
2013-07-02 15:07 ` Hendrik Brueckner
2013-10-11 7:15 ` Benjamin Herrenschmidt
2013-10-11 7:15 ` Benjamin Herrenschmidt
2013-10-11 12:47 ` Hendrik Brueckner
2013-10-11 12:47 ` Hendrik Brueckner
2013-10-11 20:43 ` Benjamin Herrenschmidt
2013-10-11 20:43 ` Benjamin Herrenschmidt
2013-10-15 15:36 ` Hendrik Brueckner
2013-10-15 15:36 ` Hendrik Brueckner
2013-10-15 20:47 ` Benjamin Herrenschmidt
2013-10-15 20:47 ` Benjamin Herrenschmidt
2013-10-16 9:04 ` Hendrik Brueckner
2013-10-16 9:04 ` Hendrik Brueckner
2013-10-16 23:21 ` Benjamin Herrenschmidt [this message]
2013-10-16 23:21 ` Benjamin Herrenschmidt
2013-10-17 8:16 ` Hendrik Brueckner
2013-10-17 8:16 ` Hendrik Brueckner
2013-07-02 15:07 ` [PATCH 2/2] tty/hvc_iucv: Disconnect IUCV connection when lowering DTR Hendrik Brueckner
2013-07-02 15:07 ` Hendrik Brueckner
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