From: Benjamin Herrenschmidt <benh@kernel•crashing.org>
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: Sat, 12 Oct 2013 07:43:24 +1100 [thread overview]
Message-ID: <1381524204.5630.91.camel@pasglop> (raw)
In-Reply-To: <20131011124707.GA6082@linux.vnet.ibm.com>
On Fri, 2013-10-11 at 14:47 +0200, Hendrik Brueckner wrote:
> The tiocmget/tiocmset callbacks are used to set and get modem status and
> triggered through an tty ioctl.
>
> The dtr_rts() callback is different and it is used for DTS/RTS handshaking
> between the hvc_console (or any other tty_port) and the tty layer. The tty
> port layer uses this callback to signal the hvc_console whether to raise or
> lower the DTR/RTS lines. This is different than the ioctl interface to
> controls the modem status.
Well, DTR at least is the same via both callbacks... Also normal handshaking
is normally RTS/CTS, only some HW setups "hijacks" DTR for RTS (old Macs come
to mind).
Cheers,
Ben.
next prev parent reply other threads:[~2013-10-11 20:43 UTC|newest]
Thread overview: 11+ 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 ` [PATCH 1/2] tty/hvc_console: Add DTR/RTS callback to handle HUPCL control Hendrik Brueckner
2013-10-11 7:15 ` Benjamin Herrenschmidt
2013-10-11 12:47 ` Hendrik Brueckner
2013-10-11 20:43 ` Benjamin Herrenschmidt [this message]
2013-10-15 15:36 ` Hendrik Brueckner
2013-10-15 20:47 ` Benjamin Herrenschmidt
2013-10-16 9:04 ` Hendrik Brueckner
2013-10-16 23:21 ` Benjamin Herrenschmidt
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
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