From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from cae.in-ulm.de (cae.in-ulm.de [217.10.14.231]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 633FE144316; Wed, 4 Sep 2024 13:58:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.10.14.231 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725458291; cv=none; b=W9z75NbgULhWFTyVxCNjf5iKeJzUL06908UdNVC0yHk2jrPDCdldydrd/s7n5ALWm4fsEus2QvAJ249pTHVmqFkodAdDs8YubxBv2XQ/zFwE2jsJLAJlXj9O5TQedvdOYlEH53owR6et/CHI0SXivcCXK0P/24w+Q54Zx5Ahgzc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725458291; c=relaxed/simple; bh=YAplyYgWPO6E3YUZiymtzPbxWQuvUbJnGyWt94aPRRM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Q/S2pgdJE9l3Or6dBapNxNSg4co/VHEvAfZHG5tg6DagzzjtdNcSNK+pQKhuQvQzI/0NckMXbiLp/YeneeEa4mnhRW+3FEOD9fTXi52bDT3HV+2Ssnj5SWrkA7PGOojYsKwJHEVgpQ8by8USHtFdQKH973HeQM6Q/saSCMd4cTE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=c--e.de; spf=pass smtp.mailfrom=c--e.de; arc=none smtp.client-ip=217.10.14.231 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=c--e.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=c--e.de Received: by cae.in-ulm.de (Postfix, from userid 1000) id 39C5D140551; Wed, 4 Sep 2024 15:58:05 +0200 (CEST) Date: Wed, 4 Sep 2024 15:58:05 +0200 From: "Christian A. Ehrhardt" To: Heikki Krogerus Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Anurag Bijea , Christian Heusel , Greg Kroah-Hartman , Dmitry Baryshkov , Jameson Thies , Abhishek Pandit-Subedi Subject: Re: [PATCH v3] usb: typec: ucsi: Fix busy loop on ASUS VivoBooks Message-ID: References: <20240903181917.617400-1-lk@c--e.de> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Hi Heikki, On Wed, Sep 04, 2024 at 03:07:45PM +0300, Heikki Krogerus wrote: > On Tue, Sep 03, 2024 at 08:19:17PM +0200, Christian A. Ehrhardt wrote: > > If the busy indicator is set, all other fields in CCI should be > > clear according to the spec. However, some UCSI implementations do > > not follow this rule and report bogus data in CCI along with the > > busy indicator. Ignore the contents of CCI if the busy indicator is > > set. > > > > If a command timeout is hit it is possible that the EVENT_PENDING > > bit is cleared while connector work is still scheduled which can > > cause the EVENT_PENDING bit to go out of sync with scheduled connector > > work. Check and set the EVENT_PENDING bit on entry to > > ucsi_handle_connector_change() to fix this. > > > > Reported-by: Anurag Bijea > > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219108 > > Bisected-by: Christian Heusel > > Tested-by: Anurag Bijea > > Fixes: de52aca4d9d5 ("usb: typec: ucsi: Never send a lone connector change ack") > > Cc: stable@vger.kernel.org > > Signed-off-by: Christian A. Ehrhardt > > --- > > drivers/usb/typec/ucsi/ucsi.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c > > index 4039851551c1..540cb1d2822c 100644 > > --- a/drivers/usb/typec/ucsi/ucsi.c > > +++ b/drivers/usb/typec/ucsi/ucsi.c > > @@ -38,6 +38,10 @@ > > > > void ucsi_notify_common(struct ucsi *ucsi, u32 cci) > > { > > + /* Ignore bogus data in CCI if busy indicator is set. */ > > + if (cci & UCSI_CCI_BUSY) > > + return; > > I started testing this and it looks like the commands never get > cancelled when the BUSY bit is set. I don't think this patch is the > problem, though. I think the BUSY handling broke earlier, probable in > 5e9c1662a89b ("usb: typec: ucsi: rework command execution functions"). > > I need to look at this a bit more carefully, but in the meantime, can > you try this: > > if (cci & UCSI_CCI_BUSY) { > complete(&ucsi->complete); > return; > } I really don't think this is the correct thing to do and it will likely make things worse. A notification with the UCSI_CCI_BUSY bit does _not_ mean that the controller is busy doing other things and cannot complete the command. Instead it is an indication that the controller _is_ working to complete our command but will take somewhat longer: Citing: | Note: If a command takes longer than MIN_TIME_TO_RESPOND_WITH_BUSY ms | for the PPM (excluding PPM to OPM communication latency) to complete, | then the PPM shall respond to the command by setting the CCI Busy | Indicator and notify the OPM. | Subsequently, when the PPM actually completes the command, the | PPM shall notify the OPM of the outcome of the command via an | asynchronous notification associated with that command. Unless I misunderstand what you are trying to do your change would cause us to needlessly abort/cancel every command that takes more than MIN_TIME_TO_RESPOND_WITH_BUSY to complete. What am I missing? Best regards, Christian