From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfgang Grandegger Subject: Re: What are you doing if the TX buffer overflows? Date: Tue, 18 Sep 2012 21:13:48 +0200 Message-ID: <5058C7EC.1080206@grandegger.com> References: <2478881.znSzbTXnK5@uschi> <505777BC.3000705@hartkopp.net> <5058659E.2010804@grandegger.com> <50586A50.5060300@pengutronix.de> <50586DE4.9020707@grandegger.com> <50587058.7090703@pengutronix.de> <50587987.3070308@grandegger.com> <50587A4F.5060105@pengutronix.de> <5058C28A.5030300@grandegger.com> <5058C505.6020605@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from ngcobalt02.manitu.net ([217.11.48.102]:46384 "EHLO ngcobalt02.manitu.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754383Ab2IRTOP (ORCPT ); Tue, 18 Sep 2012 15:14:15 -0400 In-Reply-To: <5058C505.6020605@pengutronix.de> Sender: linux-can-owner@vger.kernel.org List-ID: To: Marc Kleine-Budde Cc: Oliver Hartkopp , =?ISO-8859-1?Q?Heinz-J=FCrg?= =?ISO-8859-1?Q?en_Oertel?= , "linux-can@vger.kernel.org" On 09/18/2012 09:01 PM, Marc Kleine-Budde wrote: > On 09/18/2012 08:50 PM, Wolfgang Grandegger wrote: >> On 09/18/2012 03:42 PM, Marc Kleine-Budde wrote: >>> On 09/18/2012 03:39 PM, Wolfgang Grandegger wrote: >>>> On 09/18/2012 03:00 PM, Marc Kleine-Budde wrote: >>>>> On 09/18/2012 02:49 PM, Wolfgang Grandegger wrote: >>>>> [...] >>>>> >>>>>>> We have several customers who asked how to abort pending TX mes= sages, >>>>>>> too. Which involves: >>>>>>> a) clear the TX-queue in Linux >>>>>>> b) clear queue in hardware >>>>>>> c) abort currently transmitting CAN frame >>>>>>> >>>>>>> I think c) would be a usecase of its own, too. >>>>>> >>>>>> I think you need c) for b), at least for some controllers. These >>>>> >>>>> Yes, if it's a hardware limitation so be it. But if we design an >>>>> interface it should support "clear everything" (a+b+c), but also = just >>>>> only c. >>>> >>>> Yes, that you be nice. The only portable "clear everything" (a+b+c= ) I >>>> see is "ifconfig down -> up". This also answers you other related = mail. >>>> >>>> What do people really want/need and why? This is still not clear t= o me. >>>> More input would be nice. >>> >>> Heinz-J=FCrgen uses abort current TX Message on SJA1000, can you gi= ve us >>> more insight? I've talked to customers, e.g. they want to abort the >>> current frame if it takes "too long" to send it, because the frames= CAN >>> id priority is too low. >> >> What we could implement rather easily is a "tx-abort-last" or >> "tx-abort-all" netlink command. As this command does not make sense = when >> more than one message is pending I'm in favor of "tx-abort-last". >=20 > I like to have both commands. But then "tx-abort-all" should also clear the tx socket queue. Also be aware that more than one socket may send messages. Let's wait for more use-cases. Wolfgang.