From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Fulghum Subject: Re: [PATCH] synclink fix ldisc buffer argument Date: Mon, 03 Dec 2012 10:03:24 -0600 Message-ID: <50BCCD4C.8050209@microgate.com> References: <50B6E751.9000000@asianux.com> <20121129051335.GA4375@kroah.com> <50B6F967.3050000@asianux.com> <20121129183207.GA4688@kroah.com> <50B81F76.8020508@asianux.com> <50B8DDAC.8070901@microgate.com> <50B90D0D.9040401@microgate.com> <20121202151332.3b6a6504@pyramind.ukuu.org.uk> <20121202181057.097012c6@pyramind.ukuu.org.uk> <989CB961-79F8-479B-B16C-41358A60AC94@microgate.com> <50BC0C84.4060802@asianux.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from atl4mhob09.myregisteredsite.com ([209.17.115.47]:39212 "EHLO atl4mhob09.myregisteredsite.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753528Ab2LCQDL (ORCPT ); Mon, 3 Dec 2012 11:03:11 -0500 Received: from mailpod1.hostingplatform.com (mailpod1.networksolutionsemail.com [206.188.198.65]) by atl4mhob09.myregisteredsite.com (8.14.4/8.14.4) with ESMTP id qB3G39om021823 for ; Mon, 3 Dec 2012 11:03:09 -0500 In-Reply-To: <50BC0C84.4060802@asianux.com> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Chen Gang Cc: Alan Cox , Greg KH , Linux Kernel Mailing List , linux-serial@vger.kernel.org On 12/2/2012 8:20 PM, Chen Gang wrote: > pardon (I am just learning) > does 65535 mean HDLC_MAX_FRAME_SIZE ? > why do we need info->max_frame_size >= 4096 ? > in drivers/tty/synclink_gt.c: > 3550 if (info->max_frame_size < 4096) > 3551 info->max_frame_size = 4096; > 3552 else if (info->max_frame_size > 65535) > 3553 info->max_frame_size = 65535; > 3554 > ... > 3603 info->max_frame_size = 4096; The hardware can send and receive HDLC frames up to 64K in size. The driver defaults to 4K max frame size to save buffer space for the common case (line 3603 in alloc_dev()). The module parameter max_frame_size can override the default in add_device() (lines 3550-3554 are from add_device() range checking the module parameter) > if possible: > can we move the relative comments (which are inside function) to the > location just above ldisc_receive_buf ? The added comment from my first patch described the reuse of the data buffer as the flag buffer. Alan prefers to use a zero initialized dummy buffer for the flag buffer argument. Doing it that way, the comment is not needed. -- Paul Fulghum MicroGate Systems, Ltd. =Customer Driven, by Design= (800)444-1982 (US Sales) (512)345-7791 x102 (Direct) (512)343-9046 (Fax) Central Time Zone (GMT -6h) www.microgate.com