From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3rl8ks1swXzDr31 for ; Thu, 7 Jul 2016 04:42:44 +1000 (AEST) Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u66Iderq118222 for ; Wed, 6 Jul 2016 14:42:43 -0400 Received: from e06smtp11.uk.ibm.com (e06smtp11.uk.ibm.com [195.75.94.107]) by mx0a-001b2d01.pphosted.com with ESMTP id 2415xkbndw-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 06 Jul 2016 14:42:42 -0400 Received: from localhost by e06smtp11.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 6 Jul 2016 19:42:40 +0100 Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by d06dlp01.portsmouth.uk.ibm.com (Postfix) with ESMTP id 16BAA17D8042 for ; Wed, 6 Jul 2016 19:44:02 +0100 (BST) Received: from d06av04.portsmouth.uk.ibm.com (d06av04.portsmouth.uk.ibm.com [9.149.37.216]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u66Igc2110027284 for ; Wed, 6 Jul 2016 18:42:38 GMT Received: from d06av04.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av04.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u66Igbqr029407 for ; Wed, 6 Jul 2016 12:42:38 -0600 Subject: Re: [PATCH 11/14] cxl: Workaround PE=0 hardware limitation in Mellanox CX4 To: Ian Munsie , Michael Ellerman , Michael Neuling , Andrew Donnellan , linuxppc-dev@lists.ozlabs.org, Huy Nguyen References: <1467638532-9250-1-git-send-email-imunsie@au.ibm.com> <1467638532-9250-12-git-send-email-imunsie@au.ibm.com> From: Frederic Barrat Date: Wed, 6 Jul 2016 20:42:36 +0200 MIME-Version: 1.0 In-Reply-To: <1467638532-9250-12-git-send-email-imunsie@au.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Message-Id: <577D511C.9050601@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Le 04/07/2016 15:22, Ian Munsie a écrit : > From: Ian Munsie > > The CX4 card cannot cope with a context with PE=0 due to a hardware > limitation, resulting in: > > [ 34.166577] command failed, status limits exceeded(0x8), syndrome 0x5a7939 > [ 34.166580] mlx5_core 0000:01:00.1: Failed allocating uar, aborting > > Since the kernel API allocates a default context very early during > device init that will almost certainly get Process Element ID 0 there is > no easy way for us to extend the API to allow the Mellanox to inform us > of this limitation ahead of time. > > Instead, work around the issue by extending the XSL structure to include > a minimum PE to allocate. Although the bug is not in the XSL, it is the > easiest place to work around this limitation given that the CX4 is > currently the only card that uses an XSL. > > Signed-off-by: Ian Munsie Reviewed-by: Frederic Barrat