From nobody Mon Apr 6 14:08:41 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9D3B2ECAAD3 for ; Wed, 7 Sep 2022 08:54:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229792AbiIGIx7 (ORCPT ); Wed, 7 Sep 2022 04:53:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38084 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230265AbiIGIxf (ORCPT ); Wed, 7 Sep 2022 04:53:35 -0400 Received: from mx0b-001ae601.pphosted.com (mx0a-001ae601.pphosted.com [67.231.149.25]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4DCA2B08A6 for ; Wed, 7 Sep 2022 01:53:22 -0700 (PDT) Received: from pps.filterd (m0077473.ppops.net [127.0.0.1]) by mx0a-001ae601.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 2876sQ68005118; Wed, 7 Sep 2022 03:53:06 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cirrus.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=PODMain02222019; bh=PfmUESLoYKijI4XQrGK3nArMP4Gz6y3F+JkaqLCDJWE=; b=oGqNS83JXUjOBuJqf5qkW2p/oJARAReQDGBKgwOX+8B7ecwNKV6L06s3vaps46+EGHMW APr5BBOagmMFjUKH5i/jHV7ufS1cFFH+6117FmqF780RGoSxFhtlXYfA8h8nfF0XIAv4 UkxI6z+B8+xDIFnJ/Eoun8GVYhvV3YvBClmx5lu5FkbMAYmSrE2Ae7uU6tIVZeoFEpI9 z5ibicYZ+NZ4qpKjfUpu2IKIoF9fuhvvV3lxBfRYd+LG1tJduekx+33jzn1Cj1uJJjiP rTAsYR4j0Yz3ZcEHS95uL/csknneEaZX4KPEsnrlSX9ts6NSUvSTv1GX99C5kfWjEJZH oQ== Received: from ediex01.ad.cirrus.com ([84.19.233.68]) by mx0a-001ae601.pphosted.com (PPS) with ESMTPS id 3jc4b2dcun-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 07 Sep 2022 03:53:06 -0500 Received: from ediex01.ad.cirrus.com (198.61.84.80) by ediex01.ad.cirrus.com (198.61.84.80) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.12; Wed, 7 Sep 2022 03:53:04 -0500 Received: from ediswmail.ad.cirrus.com (198.61.86.93) by ediex01.ad.cirrus.com (198.61.84.80) with Microsoft SMTP Server id 15.2.1118.12 via Frontend Transport; Wed, 7 Sep 2022 03:53:04 -0500 Received: from debianA11184.ad.cirrus.com (unknown [198.61.65.149]) by ediswmail.ad.cirrus.com (Postfix) with ESMTP id 4CE86B06; Wed, 7 Sep 2022 08:53:04 +0000 (UTC) From: Richard Fitzgerald To: , , , CC: , , , Richard Fitzgerald Subject: [PATCH v2 3/5] soundwire: bus: Don't re-enumerate before status is UNATTACHED Date: Wed, 7 Sep 2022 09:52:57 +0100 Message-ID: <20220907085259.3602-4-rf@opensource.cirrus.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220907085259.3602-1-rf@opensource.cirrus.com> References: <20220907085259.3602-1-rf@opensource.cirrus.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Proofpoint-GUID: JZPYbelKH_jA9kRsykD8Pw5b5eZK0BSe X-Proofpoint-ORIG-GUID: JZPYbelKH_jA9kRsykD8Pw5b5eZK0BSe X-Proofpoint-Spam-Reason: safe Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Don't re-enumerate a peripheral on #0 until we have seen and handled an UNATTACHED notification for that peripheral. Without this, it is possible for the UNATTACHED status to be missed and so the slave->status remains at ATTACHED. If slave->status never changes to UNATTACHED the child driver will never be notified of the UNATTACH, and the code in sdw_handle_slave_status() will skip the second part of enumeration because the slave->status has not changed. This scenario can happen because PINGs are handled in a workqueue function which is working from a snapshot of an old PING, and there is no guarantee when this function will run. A peripheral could report attached in the PING being handled by sdw_handle_slave_status(), but has since reverted to device #0 and is then found in the loop in sdw_program_device_num(). Previously the code would not have updated slave->status to UNATTACHED because it had not yet handled a PING where that peripheral had UNATTACHED. This situation happens fairly frequently with multiple peripherals on a bus that are intentionally reset (for example after downloading firmware). Signed-off-by: Richard Fitzgerald --- drivers/soundwire/bus.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c index 1cc858b4107d..6e569a875a9b 100644 --- a/drivers/soundwire/bus.c +++ b/drivers/soundwire/bus.c @@ -773,6 +773,16 @@ static int sdw_program_device_num(struct sdw_bus *bus) if (sdw_compare_devid(slave, id) =3D=3D 0) { found =3D true; =20 + /* + * To prevent skipping state-machine stages don't + * program a device until we've seen it UNATTACH. + * Must return here because no other device on #0 + * can be detected until this one has been + * assigned a device ID. + */ + if (slave->status !=3D SDW_SLAVE_UNATTACHED) + return 0; + /* * Assign a new dev_num to this Slave and * not mark it present. It will be marked --=20 2.30.2