From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F243C43461 for ; Sun, 13 Sep 2020 12:39:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D17282158C for ; Sun, 13 Sep 2020 12:39:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="p5+1D6mg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725958AbgIMMjj (ORCPT ); Sun, 13 Sep 2020 08:39:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54356 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725927AbgIMMji (ORCPT ); Sun, 13 Sep 2020 08:39:38 -0400 Received: from mail-oi1-x243.google.com (mail-oi1-x243.google.com [IPv6:2607:f8b0:4864:20::243]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C4CC2C061573 for ; Sun, 13 Sep 2020 05:39:37 -0700 (PDT) Received: by mail-oi1-x243.google.com with SMTP id n2so14766122oij.1 for ; Sun, 13 Sep 2020 05:39:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:reply-to:references :mime-version:content-disposition:in-reply-to:user-agent; bh=l3WXaGdP8SgXL6VCI8rD1lbY8X7+MJhgv01RyK8uTDE=; b=p5+1D6mg1ApenrzHMzvr04hfK1qUgWGB3Tg9DLvHl9k67RwzlnZZifJqsKlJNxmSZ9 cc3T6cFH42iv2brYTpeR/bsLzTTe3qE8w97vwWbeqjBnYY7l0gowQor6ml30Nc25Q6pS eSMiAHsl1Q9aT+zCyOqECTKCU7lhv+Xb1+IMk1YMo0LeBuAIcjxme3uM668XXU47Er9j dZBrnZ0xsqZgLZqHH7T4HfgYtms8aVNatnUEMPiGxBPrYMl4Z1Mbh9IW9f3mTefse9dW mj+6aKEK8/nSAM2EzJFCuVwfUXfPlT1+PagXN5LCi6Cqm02xs8fnb+uXKDGGHCA3Vz/i 52Vg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :reply-to:references:mime-version:content-disposition:in-reply-to :user-agent; bh=l3WXaGdP8SgXL6VCI8rD1lbY8X7+MJhgv01RyK8uTDE=; b=KDivUOYpj8XvXWPK0PWNhVnCKGCK5C9i/7zCG8Cjl0JcBSxcaNQNufN6CWA+MI7utl gi/pl3Wh/l0PCCtQcYNH8lO6Qlq6tjz/PyYNV8MK07AIm5FNCH9nOq5dbSgyYiVOh2QF tC3QcpO5jfgpCzird3JP7d/spEL/8AhJToIy/78Qrfpmg3rjUoCH6h8+BNQYEU4vDeg3 yAa3zpJpjDteQDwMKZcejBjRwJk0vAuAoGadDCgX13z3jU+yNw4Afz9FwU4Z0bzh2Ght cA06KXnnsHp9mji4P+CmcGQ3qJf7tfWAvzajhCfrWGXIHbCy5HSfA0fMmeievEzphtTt wgvQ== X-Gm-Message-State: AOAM532y5Tf8YpS/MI+bGdC+DmydVth63x9wW7N1g/fwfdLCWxJZ1W0Y XMX8F03fznqr5+z9o41IoInvt2AFmg== X-Google-Smtp-Source: ABdhPJwoWPBCa2RxpIiOjqfQYMaTBJQTMz0eDcy/1DqzYWqRVHxuHqGPDdUD8kmuqvDxQavtMNO62g== X-Received: by 2002:a05:6808:287:: with SMTP id z7mr6377916oic.99.1600000773754; Sun, 13 Sep 2020 05:39:33 -0700 (PDT) Received: from serve.minyard.net ([47.184.170.156]) by smtp.gmail.com with ESMTPSA id e7sm1570012otk.59.2020.09.13.05.39.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 13 Sep 2020 05:39:32 -0700 (PDT) Received: from minyard.net (unknown [IPv6:2001:470:b8f6:1b:ecd3:d2ae:8b57:1a08]) by serve.minyard.net (Postfix) with ESMTPSA id D397F180056; Sun, 13 Sep 2020 12:39:31 +0000 (UTC) Date: Sun, 13 Sep 2020 07:39:30 -0500 From: Corey Minyard To: Xianting Tian Cc: arnd@arndb.de, gregkh@linuxfoundation.org, openipmi-developer@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ipmi: retry to get device id when error Message-ID: <20200913123930.GH15602@minyard.net> Reply-To: minyard@acm.org References: <20200913120203.3368-1-tian.xianting@h3c.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200913120203.3368-1-tian.xianting@h3c.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Sep 13, 2020 at 08:02:03PM +0800, Xianting Tian wrote: > We can't get bmc's device id with low probability when loading ipmi driver, > it caused bmc device register failed. This issue may caused by bad lpc > signal quality. When this issue happened, we got below kernel printks: > [Wed Sep 9 19:52:03 2020] ipmi_si IPI0001:00: IPMI message handler: device id demangle failed: -22 > [Wed Sep 9 19:52:03 2020] IPMI BT: using default values > [Wed Sep 9 19:52:03 2020] IPMI BT: req2rsp=5 secs retries=2 > [Wed Sep 9 19:52:03 2020] ipmi_si IPI0001:00: Unable to get the device id: -5 > [Wed Sep 9 19:52:04 2020] ipmi_si IPI0001:00: Unable to register device: error -5 > > When this issue happened, we want to manually unload the driver and try to > load it again, but it can't be unloaded by 'rmmod' as it is already 'in use'. I'm not sure this patch is a good idea; it would cause a long boot delay in situations where there really isn't a BMC out there. Yes, it happens. You don't have to reload the driver to add a device, though. You can hot-add devices using /sys/modules/ipmi_si/parameters/hotmod. Look in Documentation/driver-api/ipmi.rst for details. Does that work for you? -corey > > We add below 'printk' in handle_one_recv_msg(), when this issue happened, > the msg we received is "Recv: 1c 01 d5", which means the data_len is 1, > data[0] is 0xd5. > Debug code: > static int handle_one_recv_msg(struct ipmi_smi *intf, > struct ipmi_smi_msg *msg) { > printk("Recv: %*ph\n", msg->rsp_size, msg->rsp); > ... ... > } > Then in ipmi_demangle_device_id(), it returned '-EINVAL' as 'data_len < 7' > and 'data[0] != 0'. > > We used this patch to retry to get device id when error happen, we > reproduced this issue again and the retry succeed on the first retry, we > finally got the correct msg and then all is ok: > Recv: 1c 01 00 01 81 05 84 02 af db 07 00 01 00 b9 00 10 00 > > So use retry machanism in this patch to give bmc more opportunity to > correctly response kernel. > > Signed-off-by: Xianting Tian > --- > drivers/char/ipmi/ipmi_msghandler.c | 17 ++++++++++++++--- > 1 file changed, 14 insertions(+), 3 deletions(-) > > diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c > index 737c0b6b2..bfb2de77a 100644 > --- a/drivers/char/ipmi/ipmi_msghandler.c > +++ b/drivers/char/ipmi/ipmi_msghandler.c > @@ -34,6 +34,7 @@ > #include > #include > #include > +#include > > #define IPMI_DRIVER_VERSION "39.2" > > @@ -60,6 +61,9 @@ enum ipmi_panic_event_op { > #else > #define IPMI_PANIC_DEFAULT IPMI_SEND_PANIC_EVENT_NONE > #endif > + > +#define GET_DEVICE_ID_MAX_RETRY 5 > + > static enum ipmi_panic_event_op ipmi_send_panic_event = IPMI_PANIC_DEFAULT; > > static int panic_op_write_handler(const char *val, > @@ -2426,19 +2430,26 @@ send_get_device_id_cmd(struct ipmi_smi *intf) > static int __get_device_id(struct ipmi_smi *intf, struct bmc_device *bmc) > { > int rv; > - > - bmc->dyn_id_set = 2; > + unsigned int retry_count = 0; > > intf->null_user_handler = bmc_device_id_handler; > > +retry: > + bmc->dyn_id_set = 2; > + > rv = send_get_device_id_cmd(intf); > if (rv) > return rv; > > wait_event(intf->waitq, bmc->dyn_id_set != 2); > > - if (!bmc->dyn_id_set) > + if (!bmc->dyn_id_set) { > + msleep(1000); > + if (++retry_count <= GET_DEVICE_ID_MAX_RETRY) > + goto retry; > + > rv = -EIO; /* Something went wrong in the fetch. */ > + } > > /* dyn_id_set makes the id data available. */ > smp_rmb(); > -- > 2.17.1 >