From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751869AbcGAAup (ORCPT ); Thu, 30 Jun 2016 20:50:45 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:44898 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751052AbcGAAun (ORCPT ); Thu, 30 Jun 2016 20:50:43 -0400 X-IBM-Helo: d23dlp03.au.ibm.com X-IBM-MailFrom: gwshan@linux.vnet.ibm.com X-IBM-RcptTo: linux-doc@vger.kernel.org;linux-kernel@vger.kernel.org;linux-pci@vger.kernel.org Date: Fri, 1 Jul 2016 10:50:36 +1000 From: Gavin Shan To: Yongji Xie Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-doc@vger.kernel.org, bhelgaas@google.com, alex.williamson@redhat.com, aik@ozlabs.ru, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, corbet@lwn.net, warrier@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, gwshan@linux.vnet.ibm.com Subject: Re: [PATCH v3 3/7] PCI: Do not disable memory decoding in pci_reassigndev_resource_alignment() Reply-To: Gavin Shan References: <1467283993-3185-1-git-send-email-xyjxie@linux.vnet.ibm.com> <1467283993-3185-4-git-send-email-xyjxie@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1467283993-3185-4-git-send-email-xyjxie@linux.vnet.ibm.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16070100-0012-0000-0000-000001A5BE6D X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16070100-0013-0000-0000-00000580591D Message-Id: <20160701005036.GA18999@gwshan> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-06-30_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1607010006 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 30, 2016 at 06:53:09PM +0800, Yongji Xie wrote: >We should not disable memory decoding when we reassign alignment >in pci_reassigndev_resource_alignment(). It's meaningless and >have some side effect. For example, some fixup functions such as >quirk_e100_interrupt() read PCI_COMMAND_MEMORY to know whether >the devices has been initialized by the firmware or not. If we >disable memory decoding here, these functions will get a wrong >information that the devices was not initialized by the firmware >which may cause a wrong fixup. Besides, disabling memory decoding >may also break some devices that need to have memory decoding >always-on during probing. > It seems the changelog isn't correct enough if it's talking about below check in code: if (!(command & PCI_COMMAND_MEMORY) || !pci_resource_start(dev, 0)) return; >Signed-off-by: Yongji Xie >--- > drivers/pci/pci.c | 8 +------- > 1 file changed, 1 insertion(+), 7 deletions(-) > >diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c >index 6ae02de..6241cfc 100644 >--- a/drivers/pci/pci.c >+++ b/drivers/pci/pci.c >@@ -4820,7 +4820,6 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) > int i; > struct resource *r; > resource_size_t align, size; >- u16 command; > > /* We should never try to reassign VF's alignment */ > if (dev->is_virtfn) >@@ -4838,12 +4837,7 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) > return; > } > >- dev_info(&dev->dev, >- "Disabling memory decoding and releasing memory resources.\n"); >- pci_read_config_word(dev, PCI_COMMAND, &command); >- command &= ~PCI_COMMAND_MEMORY; >- pci_write_config_word(dev, PCI_COMMAND, command); >- >+ dev_info(&dev->dev, "Releasing memory resources.\n"); Is there a problem you found with PCI_COMMAND removed? If so, could you please share more details, thanks. > for (i = 0; i < PCI_BRIDGE_RESOURCES; i++) { > r = &dev->resource[i]; > if (!(r->flags & IORESOURCE_MEM)) Thanks, Gavin