From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 1C4F62765C9 for ; Mon, 18 Aug 2025 10:44:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755513875; cv=none; b=hMKKzCCI2ZsV2ziBKKNiP0Ve/adsmIIBDTn6If716sb3aewz2h/dATGBSRa8OHnjJDqOF2fsRyhD/Mg0iZ5noW5wQvbKieNCcoeCVNkSu7Mtt5zWRf/hkt3+5n2h3uD94REfM6lpHX7RiLNjXC/3FViJn7uD6crN7pSWiw4UVQE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755513875; c=relaxed/simple; bh=N5EpnPlTE+mAu+tfs/Mf8eqzzhIB/8Q1orqBob0r12Q=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=a9qZC+QxF2IYwdz3voo2NIf8E6e0gH9eV1FpsoOkFE3Jdmz+u6JQb2iUevNI+M0lEMoRPDaoYmPIHdTBPt5c/yA8aZsyWgXm1K2Azk8ywfcPUQejtIfePSA0JoE/LN+urPetrmoHgQI+CD5zkDMgjgwE8gPiJNSglpGoAk1/SE8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=g/FwBXaW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="g/FwBXaW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 26936C4CEEB; Mon, 18 Aug 2025 10:44:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755513873; bh=N5EpnPlTE+mAu+tfs/Mf8eqzzhIB/8Q1orqBob0r12Q=; h=Subject:To:Cc:From:Date:From; b=g/FwBXaWw1q54Y3TGYqM9eCUKLCxG7ZDq1OPqn8x7wfUKy/OwbjOrhFl0HKmex2jo N5bibTMapdtJKSnkf7G027fyfX7qsuENtLiifa5ucvEoKbYFfwJn2mUmth4c5c6UO1 GSnagustIhZEttPUYf9e+rX8BKPrNFhQFcgrN7f8= Subject: FAILED: patch "[PATCH] usb: typec: fusb302: cache PD RX state" failed to apply to 6.12-stable tree To: sebastian.reichel@collabora.com,gregkh@linuxfoundation.org,heikki.krogerus@linux.intel.com,stable@kernel.org Cc: From: Date: Mon, 18 Aug 2025 12:44:30 +0200 Message-ID: <2025081830-selected-dandelion-46ec@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x 1e61f6ab08786d66a11cfc51e13d6f08a6b06c56 # git commit -s git send-email --to '' --in-reply-to '2025081830-selected-dandelion-46ec@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 1e61f6ab08786d66a11cfc51e13d6f08a6b06c56 Mon Sep 17 00:00:00 2001 From: Sebastian Reichel Date: Fri, 4 Jul 2025 19:55:06 +0200 Subject: [PATCH] usb: typec: fusb302: cache PD RX state This patch fixes a race condition communication error, which ends up in PD hard resets when losing the race. Some systems, like the Radxa ROCK 5B are powered through USB-C without any backup power source and use a FUSB302 chip to do the PD negotiation. This means it is quite important to avoid hard resets, since that effectively kills the system's power-supply. I've found the following race condition while debugging unplanned power loss during booting the board every now and then: 1. lots of TCPM/FUSB302/PD initialization stuff 2. TCPM ends up in SNK_WAIT_CAPABILITIES (tcpm_set_pd_rx is enabled here) 3. the remote PD source does not send anything, so TCPM does a SOFT RESET 4. TCPM ends up in SNK_WAIT_CAPABILITIES for the second time (tcpm_set_pd_rx is enabled again, even though it is still on) At this point I've seen broken CRC good messages being send by the FUSB302 with a logic analyzer sniffing the CC lines. Also it looks like messages are being lost and things generally going haywire with one of the two sides doing a hard reset once a broken CRC good message was send to the bus. I think the system is running into a race condition, that the FIFOs are being cleared and/or the automatic good CRC message generation flag is being updated while a message is already arriving. Let's avoid this by caching the PD RX enabled state, as we have already processed anything in the FIFOs and are in a good state. As a side effect that this also optimizes I2C bus usage :) As far as I can tell the problem theoretically also exists when TCPM enters SNK_WAIT_CAPABILITIES the first time, but I believe this is less critical for the following reason: On devices like the ROCK 5B, which are powered through a TCPM backed USB-C port, the bootloader must have done some prior PD communication (initial communication must happen within 5 seconds after plugging the USB-C plug). This means the first time the kernel TCPM state machine reaches SNK_WAIT_CAPABILITIES, the remote side is not sending messages actively. On other devices a hard reset simply adds some extra delay and things should be good afterwards. Fixes: c034a43e72dda ("staging: typec: Fairchild FUSB302 Type-c chip driver") Cc: stable Signed-off-by: Sebastian Reichel Reviewed-by: Heikki Krogerus Link: https://lore.kernel.org/r/20250704-fusb302-race-condition-fix-v1-1-239012c0e27a@kernel.org Signed-off-by: Greg Kroah-Hartman diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c index f2801279c4b5..a4ff2403ddd6 100644 --- a/drivers/usb/typec/tcpm/fusb302.c +++ b/drivers/usb/typec/tcpm/fusb302.c @@ -104,6 +104,7 @@ struct fusb302_chip { bool vconn_on; bool vbus_on; bool charge_on; + bool pd_rx_on; bool vbus_present; enum typec_cc_polarity cc_polarity; enum typec_cc_status cc1; @@ -841,6 +842,11 @@ static int tcpm_set_pd_rx(struct tcpc_dev *dev, bool on) int ret = 0; mutex_lock(&chip->lock); + if (chip->pd_rx_on == on) { + fusb302_log(chip, "pd is already %s", str_on_off(on)); + goto done; + } + ret = fusb302_pd_rx_flush(chip); if (ret < 0) { fusb302_log(chip, "cannot flush pd rx buffer, ret=%d", ret); @@ -863,6 +869,8 @@ static int tcpm_set_pd_rx(struct tcpc_dev *dev, bool on) str_on_off(on), ret); goto done; } + + chip->pd_rx_on = on; fusb302_log(chip, "pd := %s", str_on_off(on)); done: mutex_unlock(&chip->lock);