Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752594Ab0FVWQW (ORCPT ); Tue, 22 Jun 2010 18:16:22 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:51484 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751066Ab0FVWQU (ORCPT ); Tue, 22 Jun 2010 18:16:20 -0400 Date: Tue, 22 Jun 2010 23:21:08 +0100 From: Alan Cox To: Samo Pogacnik Cc: linux-embedded , linux kernel Subject: Re: [PATCH] detour TTY driver - now ttyprintk Message-ID: <20100622232108.26752ff8@lxorguk.ukuu.org.uk> In-Reply-To: <1277244410.2195.47.camel@itpsd6lap> References: <1273918658.2341.17.camel@itpsd6lap> <1275171436.2122.29.camel@itpsd6lap> <20100529235402.296406d9@lxorguk.ukuu.org.uk> <1275175983.2122.42.camel@itpsd6lap> <1276123020.16010.97.camel@itpsd6lap> <20100611134455.3fa7d563@lxorguk.ukuu.org.uk> <1276291932.2154.45.camel@itpsd6lap> <20100621153858.444695c0@lxorguk.ukuu.org.uk> <1277244410.2195.47.camel@itpsd6lap> X-Mailer: Claws Mail 3.7.6 (GTK+ 2.18.9; 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 Content-Length: 960 Lines: 20 > For correct flow control, i suppose current empty space of the real > (final) printk buffer is needed. On the other hand my intermediate Console drivers have their own buffering so that doesn't really work. If you want to just avoid explosions then you don't need to be quite so clever > in some logical manner. And the other would be to use ratelimit support > to switch between max and zero in write_room answer and remove other > retelimit response? Yes - except that a driver isn't permitted to reduce the write room space by more than bytes written. That is if you offer 512 bytes you can't offer 0 until 512 bytes have been written - hence the design of the pseudo code I posted in the previous message. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/