From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7E1052E282B for ; Thu, 23 Apr 2026 03:50:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776916213; cv=none; b=IXYcA0A3+SKeFStQUu0vriIeiizgf1ol8P/AWVhggoWgSk0KxJTecfvzqa6uzUHekZdwlQC68uAB0FQO0myLIkeE0X0YXRZtD3MyQMgtiSSBYCqXrGbyyQhpjAoImAuyW3htiSugyWN7X5oahfEYa9wDuH8oMBo7pt13GLw2Q4s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776916213; c=relaxed/simple; bh=ZdL+/jN/ovOG7UfEMywWY7Pd2rVoztzv4iswm0WEv7g=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Hb2VkoCTgfkxdJCnG9eKotAzuDbxNKfrS2NTZcDeDrCyG3yuwfN6RzIvdyXTYStzVSsOu+62I+R98v0FAk9eq+HzwPM4NqLs26b7H7crtv1qhVszOCx3/GyJ5gmnU3tn4tIAmT6udSOnxYgKV99km9+0HnJ2Oe7fIGekFZ8SH2c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1wFl4i-0005Fc-Sv; Thu, 23 Apr 2026 05:50:00 +0200 Received: from pty.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::c5]) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1wFl4i-006laS-1E; Thu, 23 Apr 2026 05:50:00 +0200 Received: from ore by pty.whiteo.stw.pengutronix.de with local (Exim 4.98.2) (envelope-from ) id 1wFl4i-0000000AQQ6-18j7; Thu, 23 Apr 2026 05:50:00 +0200 Date: Thu, 23 Apr 2026 05:50:00 +0200 From: Oleksij Rempel To: Alexander =?utf-8?B?SMO2bHps?= Cc: robin@protonic.nl, linux-kernel@vger.kernel.org, kernel@pengutronix.de, linux-can@vger.kernel.org Subject: Re: [PATCH] can: j1939: fix wrong rx timeout for CTS hold messages Message-ID: References: <20260421153152.87772-3-alexander.hoelzl@gmx.net> Precedence: bulk X-Mailing-List: linux-can@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260421153152.87772-3-alexander.hoelzl@gmx.net> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-can@vger.kernel.org Hi Alexander, On Tue, Apr 21, 2026 at 05:31:54PM +0200, Alexander Hölzl wrote: > In J1939 segmented transport, a CTS message with data byte 2 set to zero is interpreted as a hold message. > This instructs the transmitter of the segmented message to hold the connection open but to delay sending. > According to the J1939-21 standard, section 5.10.2.4 the timeout T4 after which an held open session is invalidated is > 1050 ms, not 550 as implemented currently. > The 550 ms are problematic if a device uses hold messages and assumes it can wait for more than 550 ms before it has > to resend the hold message. > > This patch changes the T4 timeout used in the implementation from 550 ms to 1050. > > Signed-off-by: Alexander Hölzl LGTM. Thank you! Acked-by: Oleksij Rempel Sashico detected one more potential issue, not related to this patch: https://sashiko.dev/#/patchset/20260421153152.87772-3-alexander.hoelzl%40gmx.net If you have time, can you please verify it? Best Regards, Oleksij -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |