From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762435Ab2DLJpk (ORCPT ); Thu, 12 Apr 2012 05:45:40 -0400 Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:35074 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762371Ab2DLJpi (ORCPT ); Thu, 12 Apr 2012 05:45:38 -0400 Date: Thu, 12 Apr 2012 10:47:58 +0100 From: Alan Cox To: "Shankarmurthy, Akshay" Cc: "linux-serial@vger.kernel.org" , "alan@linux.intel.com" , "gregkh@linuxfoundation.org" , "paul.gortmaker@windriver.com" , "jamie@jamieiles.com" , "swarren@nvidia.com" , "dianders@chromium.org" , "davinci-linux-open-source@linux.davincidsp.com" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] serial: 8250: Add cpufreq support Message-ID: <20120412104758.3fc8085d@pyramind.ukuu.org.uk> In-Reply-To: <6F6B80BD2E18844D97BB4B51FE3705C83179146B@DBDE01.ent.ti.com> References: <1333433022-5455-1-git-send-email-akshay.s@ti.com> <20120403105530.7fa3bce7@pyramind.ukuu.org.uk> <6F6B80BD2E18844D97BB4B51FE3705C831790EA0@DBDE01.ent.ti.com> <20120405115322.15e6088c@pyramind.ukuu.org.uk> <6F6B80BD2E18844D97BB4B51FE3705C83179146B@DBDE01.ent.ti.com> X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.8; x86_64-redhat-linux-gnu) Face: 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 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > > I will have a look at this and add the lock if necessary. > > > > At the very least you need reference counts held on the tty struct and to allow for the tty having vanished under you. > > > > I am planning to add "tty->termios_mutex" lock. Any comments ? Explain how this will help. You need a reference count to the tty itself. > I understand this and planning to avoid unnecessary registration like these. > As a solution, UART port's cpu freq status will be sent from the board file. > Adding a member to the structure "plat_serial8250_port" which says whether > a port requires cpu freq registration or not. cpu freq register function is > called in the driver depending upon the status of this structure member. > I can update the patch accordingly and send out a version 2 to the list. That sounds sensible. Alan