Messages in this thread | | | Date | Wed, 24 Mar 2010 23:02:51 +0530 (IST) | From | Pavan Savoy <> | Subject | Re: [PATCH 4/6] drivers:misc: sources for Init manager module |
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--- On Wed, 24/3/10, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> From: Alan Cox <alan@lxorguk.ukuu.org.uk> > Subject: Re: [PATCH 4/6] drivers:misc: sources for Init manager module > To: "Pavan Savoy" <pavan_savoy@yahoo.co.in> > Cc: "Marcel Holtmann" <marcel@holtmann.org>, "Greg KH" <gregkh@suse.de>, "PavanSavoy" <pavan_savoy@ti.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> > Date: Wednesday, 24 March, 2010, 10:56 PM > > Isn't there a mechanism for the > tty_set_ldisc to do what _open does ? > > I mean there might be plenty of devices on UART which > might not need /dev/tty at all ? i.e An App need not open > for a ldisc to be installed. > > There is no mechanism to have an open tty without having an > open file > attached to it - and changing that would be very very non > trivial. Plus > you still need a way to tell the kernel you want the device > in question > active. That probably should get addressed some day but its > not a quick > fix up!
Which puts me back to square 1, the requirement is TTY device should be open, only when either BT, FM or GPS would want to use it. [with your patch one of the steps of installing ldisc would be reduced upon opening].
Now from kernel-space which is the first to get notification about requirement of BT/FM or GPS, I somehow have to communicate it to user-space, without the much disliked sysfs entry method.
How do I tell the user-space when I want the TTY device to be opened ? Actually why do I even need a TTY device in this case - right ? ldisc driver can do the tty->ops->write and tty_read and put it up on different interfaces like eth0/hci0 or /dev/radio0 etc..
That would mean, a device can be on UART, a ldisc driver attached to it, and doesn't require a user-space daemon to maintain the device node.
> > Alan >
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