From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932382Ab0CXRc5 (ORCPT ); Wed, 24 Mar 2010 13:32:57 -0400 Received: from web94901.mail.in2.yahoo.com ([203.104.17.136]:38829 "HELO web94901.mail.in2.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S932322Ab0CXRcy convert rfc822-to-8bit (ORCPT ); Wed, 24 Mar 2010 13:32:54 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.co.in; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=h6vFObYwkHZxCGyXpiE5jLnhb9/bhyJ/GWG/OPeLTwiWUzkrQ1pUt16HO5pj7CcbmwSniNnLUT3JzPZrb8wMnTgrcJEbAX9cAgXHOulqovO9Ly8xml1mixDWOrbZ8OM1ks8aSQCtZVU3inzwCV3r2pfG7l6Gj78vEqqfEe/78Jk=; Message-ID: <669779.38970.qm@web94901.mail.in2.yahoo.com> X-YMail-OSG: 8lTw2aEVM1ng33ot9pKBoC.s5H85D3QT7IkyWE_6ThbKd8a N9.QKnrbCiZ0OYNvwsuVGUN279BEpxFkm5.eie9YQiC4jh1KpPpB2jcVKd0t 1w9W8UKrKf1IzcnJ7cewy6rRT1ft99o7MmPkB8YAgKyj4tnlHn08cIQWPMM_ hg26tLGKzpwB38mp3q_O4QHr7PR5OlmqL5FhBppRL7IX12gDfwd1FHJ5FmZ1 M5YJGsupVKv7pHfd4HsJpq1bicbvTaGTd8JamucN0jihiitHFvfc529iCQfr uIPR3LsBjmyNJybXtxpXlx3s- X-Mailer: YahooMailClassic/10.0.8 YahooMailWebService/0.8.100.260964 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 To: Alan Cox Cc: Marcel Holtmann , Greg KH , PavanSavoy , "linux-kernel@vger.kernel.org" In-Reply-To: <20100324172647.572e3cb8@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --- On Wed, 24/3/10, Alan Cox wrote: > From: Alan Cox > Subject: Re: [PATCH 4/6] drivers:misc: sources for Init manager module > To: "Pavan Savoy" > Cc: "Marcel Holtmann" , "Greg KH" , "PavanSavoy" , "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 > Your Mail works best with the New Yahoo Optimized IE8. Get it NOW! http://downloads.yahoo.com/in/internetexplorer/