From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay4-d.mail.gandi.net (relay4-d.mail.gandi.net [217.70.183.196]) (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 E7D461DA59 for ; Fri, 20 Oct 2023 15:20:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="Fe+FfZGa" Received: by mail.gandi.net (Postfix) with ESMTPSA id 8A0F0E0009; Fri, 20 Oct 2023 15:20:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1697815207; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=oaHjuPcslWN24KOkrEWK0l5r712keu9E2N1sB5NoPOs=; b=Fe+FfZGaDRfcO7OxSpnI7HBHq7pQthX5q1wmELp/2TZ6CBB/BSEsazaWzWmcdM+MsLXzbb tpnZ6nvC76Bz/OIBqfIaIfRJd8qI1EE+dx2Kk5mY9KZ9qpBoWbNQzSoTuXIFPfjp3DiUJp r1VMfnXib18izsQDF4BpRubDCSQYlDe9WiUdZ2r0/gbpHt8g8SbGtdy8o4RuNvtsMgpTq5 373/zLtnSo+Caz8d3a+Yx058Mf59Lj7KVWms57EglSS1+nBkvqL5nE7cnEL4kWFhMOHOav wVsfU1yaDInUxUJYJ2vR3lZVX5ZlAGBHzCPihp906pKce+SidNAM/DLo3ysA1g== Date: Fri, 20 Oct 2023 17:20:06 +0200 From: Miquel Raynal To: Frank Li Cc: alexandre.belloni@bootlin.com, conor.culhane@silvaco.com, imx@lists.linux.dev, joe@perches.com, linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 Resent 6/6] i3c: master: svc: fix random hot join failure since timeout error Message-ID: <20231020172006.5de0998b@xps-13> In-Reply-To: References: <20231018155926.3305476-1-Frank.Li@nxp.com> <20231018155926.3305476-7-Frank.Li@nxp.com> <20231019084452.11fd0645@xps-13> <20231020160645.67e678ee@xps-13> <20231020163525.66485920@xps-13> Organization: Bootlin X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: imx@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-GND-Sasl: miquel.raynal@bootlin.com Hi Frank, Frank.li@nxp.com wrote on Fri, 20 Oct 2023 10:47:52 -0400: > On Fri, Oct 20, 2023 at 04:35:25PM +0200, Miquel Raynal wrote: > > Hi Frank, > >=20 > > Frank.li@nxp.com wrote on Fri, 20 Oct 2023 10:18:55 -0400: > > =20 > > > On Fri, Oct 20, 2023 at 04:06:45PM +0200, Miquel Raynal wrote: =20 > > > > Hi Frank, > > > >=20 > > > > Frank.li@nxp.com wrote on Thu, 19 Oct 2023 11:39:42 -0400: > > > > =20 > > > > > On Thu, Oct 19, 2023 at 08:44:52AM +0200, Miquel Raynal wrote: = =20 > > > > > > Hi Frank, > > > > > >=20 > > > > > > Frank.Li@nxp.com wrote on Wed, 18 Oct 2023 11:59:26 -0400: > > > > > > =20 > > > > > > > master side report: > > > > > > > silvaco-i3c-master 44330000.i3c-master: Error condition: MS= TATUS 0x020090c7, MERRWARN 0x00100000 > > > > > > >=20 > > > > > > > BIT 20: TIMEOUT error > > > > > > > The module has stalled too long in a frame. This happens wh= en: > > > > > > > - The TX FIFO or RX FIFO is not handled and the bus is stuc= k in the > > > > > > > middle of a message, > > > > > > > - No STOP was issued and between messages, > > > > > > > - IBI manual is used and no decision was made. =20 > > > > > >=20 > > > > > > I am still not convinced this should be ignored in all cases. > > > > > >=20 > > > > > > Case 1 is a problem because the hardware failed somehow. =20 > > > > >=20 > > > > > But so far, no action to handle this case in current code. =20 > > > >=20 > > > > Yes, but if you detect an issue and ignore it, it's not better than > > > > reporting it without handling it. Instead of totally ignoring this I > > > > would at least write a debug message (identical to what's below) be= fore > > > > returning false, even though I am not convinced unconditionally > > > > returning false here is wise. If you fail a hardware sequence becau= se > > > > you added a printk, it's a problem. Maybe you consider this line as > > > > noise, but I believe it's still an error condition. Maybe, however, > > > > this bit gets set after the whole sequence, and this is just a "bus > > > > is idle" condition. If that's the case, then you need some > > > > additional heuristics to properly ignore the bit? > > > > =20 > > >=20 > > > dev_err(master->dev, = =20 > > > "Error condition: MSTATUS 0x%08x, MERRWARN 0x= %08x\n", > > > mstatus, merrwarn); > > > + > > > + /* ignore timeout error */ > > > + if (merrwarn & SVC_I3C_MERRWARN_TIMEOUT) > > > + return false; > > > + > > >=20 > > > Is it okay move SVC_I3C_MERRWARN_TIMEOUT after dev_err? =20 > >=20 > > I think you mentioned earlier that the problem was not the printk but > > the return value. So perhaps there is a way to know if the timeout > > happened after a transaction and was legitimate or not? =20 >=20 > Error message just annoise user, don't impact function. But return false > let IBI thread running to avoid dead lock.=20 >=20 > >=20 > > In any case we should probably lower the log level for this error. =20 >=20 > Only SVC_I3C_MERRWARN_TIMEOUT is warning >=20 > Maybe below logic is better >=20 > if (merrwarn & SVC_I3C_MERRWARN_TIMEOUT) { > dev_dbg(master->dev,=20 > "Error condition: MSTATUS 0x%08x, MERRWARN 0x%08x= \n", > mstatus, merrwarn); > return false; > }=20 > =09 > dev_err(master->dev, =20 > "Error condition: MSTATUS 0x%08x, MERRWARN 0x%08x\n", > mstatus, merrwarn);=20 > .... >=20 Yes, this looks better but I wonder if we should add an additional condition to just return false in this case; something saying "this timeout is legitimate and has no impact". Thanks, Miqu=C3=A8l