From nobody Fri Apr 3 08:26:50 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 707D3ECAAD3 for ; Wed, 14 Sep 2022 16:03:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230001AbiINQDc (ORCPT ); Wed, 14 Sep 2022 12:03:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229493AbiINQDa (ORCPT ); Wed, 14 Sep 2022 12:03:30 -0400 Received: from mx0b-001ae601.pphosted.com (mx0a-001ae601.pphosted.com [67.231.149.25]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 778856A490 for ; Wed, 14 Sep 2022 09:03:29 -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 28EDgEGI005943; Wed, 14 Sep 2022 11:02:58 -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=jSHVQM4f5c6nFOJUjjIDepmDXBFYw20rCfoBuGjpZxs=; b=LbWAVZ3JGBBzCZCY+jQwN45OrJLq24z2wZ6a3YlT1TioVjw7fVLXfOB45UVlEMrP/Ray 0Ncn/l0TXBHucxSgK+3iRtNz6NJNLVGwrOn6heS0lhRWsRuZnCm9AMWsXi5iE4fkS1ax B2uyPS2dMzRQIcFV4WLpXn0BzOTpaMDO44Hz4dirqwNok7A06vfH0gCsDzsIhp5qhgVk QaVxDnkFReJ5F1zPvXq0yTnU6erawsgwkcoYqlA1pjWTg2X9vys5Qvad3Ipbx+e0peWw oAO7LXYJqZzdNEi9JySMZtWU6iumHjnjIbs6FiDCPH/tVNx6AmvLAKPxOKKok2tojy03 +g== Received: from ediex02.ad.cirrus.com ([84.19.233.68]) by mx0a-001ae601.pphosted.com (PPS) with ESMTPS id 3jjy05h8em-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 14 Sep 2022 11:02:58 -0500 Received: from ediex01.ad.cirrus.com (198.61.84.80) by ediex02.ad.cirrus.com (198.61.84.81) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.12; Wed, 14 Sep 2022 11:02:55 -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, 14 Sep 2022 11:02:55 -0500 Received: from edi-sw-dsktp-006.ad.cirrus.com (edi-sw-dsktp-006.ad.cirrus.com [198.90.251.95]) by ediswmail.ad.cirrus.com (Postfix) with ESMTP id BD12511C7; Wed, 14 Sep 2022 16:02:55 +0000 (UTC) From: Richard Fitzgerald To: , , , CC: , , , Richard Fitzgerald Subject: [PATCH v4 3/5] soundwire: bus: Don't re-enumerate before status is UNATTACHED Date: Wed, 14 Sep 2022 17:02:46 +0100 Message-ID: <20220914160248.1047627-4-rf@opensource.cirrus.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220914160248.1047627-1-rf@opensource.cirrus.com> References: <20220914160248.1047627-1-rf@opensource.cirrus.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Proofpoint-GUID: -gdhMwViXDGTP4Urpmc0oSg-yySIbC0K X-Proofpoint-ORIG-GUID: -gdhMwViXDGTP4Urpmc0oSg-yySIbC0K 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 Reviewed-by: Pierre-Louis Bossart --- 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