From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:52202 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752681AbcLTXHE (ORCPT ); Tue, 20 Dec 2016 18:07:04 -0500 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id uBKN4TM8081351 for ; Tue, 20 Dec 2016 18:07:04 -0500 Received: from e23smtp04.au.ibm.com (e23smtp04.au.ibm.com [202.81.31.146]) by mx0a-001b2d01.pphosted.com with ESMTP id 27f77us4cj-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 20 Dec 2016 18:07:03 -0500 Received: from localhost by e23smtp04.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 21 Dec 2016 09:07:01 +1000 Received: from d23relay09.au.ibm.com (d23relay09.au.ibm.com [9.185.63.181]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id D6DFC2CE8057 for ; Wed, 21 Dec 2016 10:06:58 +1100 (EST) Received: from d23av06.au.ibm.com (d23av06.au.ibm.com [9.190.235.151]) by d23relay09.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id uBKN6wqh29163612 for ; Wed, 21 Dec 2016 10:06:58 +1100 Received: from d23av06.au.ibm.com (localhost [127.0.0.1]) by d23av06.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id uBKN6waW004521 for ; Wed, 21 Dec 2016 10:06:58 +1100 Date: Wed, 21 Dec 2016 10:06:57 +1100 From: Gavin Shan To: Greg KH Cc: Gavin Shan , linuxppc-dev@lists.ozlabs.org, stable@vger.kernel.org, #v4.9+@gwshan.ozlabs.ibm.com Subject: Re: [PATCH] drivers/pci/hotplug: Handle presence detection change properly Reply-To: Gavin Shan References: <1482216573-21487-1-git-send-email-gwshan@linux.vnet.ibm.com> <20161220093709.GA12938@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161220093709.GA12938@kroah.com> Message-Id: <20161220230657.GA7066@gwshan> Sender: stable-owner@vger.kernel.org List-ID: On Tue, Dec 20, 2016 at 10:37:09AM +0100, Greg KH wrote: >On Tue, Dec 20, 2016 at 05:49:33PM +1100, Gavin Shan wrote: >> The surprise hotplug is driven by interrupt in PowerNV PCI hotplug >> driver. In the interrupt handler, pnv_php_interrupt(), we bail when >> pnv_pci_get_presence_state() returns zero wrongly. It causes the >> presence change event is always ignored incorrectly. >> >> This fixes the issue by bailing on error (non-zero value) returned >> from pnv_pci_get_presence_state(). >> >> Fixes: 360aebd85a4 ("drivers/pci/hotplug: Support surprise hotplug in powernv driver") >> Cc: stable@vger.kernel.org #v4.9+ >> Reported-by: Hank Chang >> Signed-off-by: Gavin Shan >> Tested-by: Willie Liauw >> --- >> drivers/pci/hotplug/pnv_php.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c >> index 56efaf7..38a2309 100644 >> --- a/drivers/pci/hotplug/pnv_php.c >> +++ b/drivers/pci/hotplug/pnv_php.c >> @@ -707,8 +707,12 @@ static irqreturn_t pnv_php_interrupt(int irq, void *data) >> added = !!(lsts & PCI_EXP_LNKSTA_DLLLA); >> } else if (sts & PCI_EXP_SLTSTA_PDC) { >> ret = pnv_pci_get_presence_state(php_slot->id, &presence); >> - if (!ret) >> + if (ret) { >> + dev_warn(&pdev->dev, "PCI slot [%s] error %d handling PDC event (0x%04x)\n", >> + php_slot->name, ret, sts); > >What can a user do with this warning? > This warning is to catch developer's attention only. It's very rare for pnv_pci_get_presence_state() to fail as it simply checks hardware regiter bit (from Slot Status regsiter in PCIe capability or PHB's Hotplug Override register) in the skiboot firmware. User needs to retry the operation (hot-add or hot-remove) when seeing this warning. Greg, please let me know if below message is better? dev_warn(&pdev->dev, "PCI slot [%s] error %d getting presence status on event 0x%04x, to retry the operation.\n", php_slot->name, ret, sts); Thanks, Gavin