From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: MIME-Version: 1.0 In-Reply-To: <20141030170913.GA6982@google.com> References: <1414621570-20777-1-git-send-email-yinghai@kernel.org> <20141030170913.GA6982@google.com> Date: Thu, 30 Oct 2014 11:57:56 -0700 Message-ID: Subject: Re: [PATCH] PCI: fix sriov enabling with virtual bus From: Yinghai Lu To: Bjorn Helgaas Cc: "linux-pci@vger.kernel.org" , Linux Kernel Mailing List , "Rafael J. Wysocki" , ACPI Devel Maling List Content-Type: text/plain; charset=UTF-8 Sender: linux-acpi-owner@vger.kernel.org List-ID: On Thu, Oct 30, 2014 at 10:09 AM, Bjorn Helgaas wrote: > [+cc Rafael, linux-acpi] > This raises the question of what the correct behavior should be. Your > patch certainly avoids the NULL pointer dereference. It does so by making > acpi_pci_get_bridge_handle() fail gracefully, which means we will not look > for _HPP/_HPX for VF devices. Is that what we want? > > Most of the fields included in _HPX are read-only or not applicable for > VFs, but we need to at least ask the question of whether we want to > completely ignore _HPX for VFs. If we do, I think maybe we should make > that more explicit in the code, e.g., by adding an explicit test of > dev->is_virtfn, instead of relying on this special case behavior of > acpi_pci_get_bridge_handle() that in turn depends on the obscure property > of a VF not having a bridge device. > > Personally, I think that since the _HPX spec doesn't mention VFs at all, we > might want to assume that _HPX should apply to VFs, just like it applies to > PFs. I can imagine future _HPX record formats, or non-ACPI firmware > configuration hints, that *would* apply to VFs, so it seems like it would > be pretty arbitrary to say "we won't configure VF devices at all." Yes, VF should be treated as PF if possible. > >> Add checking with pbus->slef and bail out early. >> >> Fixing: commit 6cd33649fa83 ("PCI: Add pci_configure_device() during enumeration") > > Thanks for including this, but why not use the same format everybody else > does: > > Fixes: 6cd33649fa83 ("PCI: Add pci_configure_device() during enumeration") will do that later. Is that formalized ? checkpatch.pl only need 12 commit code, and (" ..") format. Yinghai