Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752976AbZI3JFn (ORCPT ); Wed, 30 Sep 2009 05:05:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751987AbZI3JFm (ORCPT ); Wed, 30 Sep 2009 05:05:42 -0400 Received: from mail-ew0-f211.google.com ([209.85.219.211]:45527 "EHLO mail-ew0-f211.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751405AbZI3JFl (ORCPT ); Wed, 30 Sep 2009 05:05:41 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=TR6VZVMt+9K7RK5eSeh8IKbvprnZwoeUxUV6Ux0zTNlDPfCh0xngaoBwlFkNsHNM26 fUI4H9HvNxtktt+GuNN6qA1B+NGYbmWto/qgjAdBfLosArWbNoFNJpEqpE7NpCwJaLqL K3fRGcY+vN+4TGLNVo7lOUiFI7h6aQTCRu+kU= Date: Wed, 30 Sep 2009 11:05:41 +0200 From: Johan Hovold To: Alan Cox Cc: Johan Hovold , Michael Trimarchi , Oliver Neukum , Greg Kroah-Hartman , linux-usb@vger.kernel.org, Alan Cox , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH] USB: ftdi_sio: Remove tty->low_latency. Message-ID: <20090930090541.GA13263@localhost> References: <20090924154023.GA27480@localhost> <200909242103.48562.oliver@neukum.org> <20090924202107.4730f2af@lxorguk.ukuu.org.uk> <20090924211459.GB27963@localhost> <4ABD020B.4040901@gandalf.sssup.it> <20090929145514.GF2152@localhost> <20090929235232.1ae6c63b@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090929235232.1ae6c63b@lxorguk.ukuu.org.uk> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 903 Lines: 26 On Tue, Sep 29, 2009 at 11:52:32PM +0100, Alan Cox wrote: > > As it stands today ftdi_sio does indeed call tty_flip_buffer_push from > > interrupt context with low_latency set and that is obviously incorrect, > > right? > > It seems to do it from a work queue - or did I miss a case ? The function used for deferred work is actually called directly from ftdi_read_bulk_callback: ftdi_process_read(&priv->rx_work.work); It only gets scheduled on the work queue when unthrottled (or if tty_buffer_request_room(tty, length) < length before serial_throttle is called). So basically, unless throttled, it is always called from interrupt context. /Johan -- 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/