From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:35113 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752845AbbC3IcN (ORCPT ); Mon, 30 Mar 2015 04:32:13 -0400 Date: Mon, 30 Mar 2015 10:31:54 +0200 From: "Michael S. Tsirkin" To: Greg KH Cc: linux-kernel@vger.kernel.org, Bjorn Helgaas , Jonathan Corbet , "David S. Miller" , Hans Verkuil , Mauro Carvalho Chehab , Alexei Starovoitov , stephen hemminger , Masahiro Yamada , Andy Shevchenko , Andy Lutomirski , Rasmus Villemoes , Stephane Eranian , Huang Rui , Peter Neubauer , linux-pci@vger.kernel.org, linux-doc@vger.kernel.org, linux-api@vger.kernel.org Subject: Re: [PATCH 01/86] pci: export pci_ids.h Message-ID: <20150330101830-mutt-send-email-mst@redhat.com> References: <1427635734-24786-1-git-send-email-mst@redhat.com> <1427635734-24786-2-git-send-email-mst@redhat.com> <20150329204047.GA5902@kroah.com> <20150330083707-mutt-send-email-mst@redhat.com> <20150330065522.GA10105@kroah.com> <20150330085617-mutt-send-email-mst@redhat.com> <20150330075331.GA17823@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20150330075331.GA17823@kroah.com> Sender: linux-pci-owner@vger.kernel.org List-ID: On Mon, Mar 30, 2015 at 09:53:31AM +0200, Greg KH wrote: > On Mon, Mar 30, 2015 at 09:15:26AM +0200, Michael S. Tsirkin wrote: > > On Mon, Mar 30, 2015 at 08:55:22AM +0200, Greg KH wrote: > > > On Mon, Mar 30, 2015 at 08:48:44AM +0200, Michael S. Tsirkin wrote: > > > > On Sun, Mar 29, 2015 at 10:40:47PM +0200, Greg KH wrote: > > > > > On Sun, Mar 29, 2015 at 03:37:01PM +0200, Michael S. Tsirkin wrote: > > > > > > The macros in pci_ids.h are pretty useful for userspace > > > > > > using the pci sysfs interface. > > > > > > At the moment userspace is forced to duplicate these macros > > > > > > (e.g. QEMU does this), it is better to expose them in > > > > > > /usr/include/linux/pci_ids.h so everyone can just include > > > > > > this header. > > > > > > > > > > > > Signed-off-by: Michael S. Tsirkin > > > > > > --- > > > > > > include/linux/pci_ids.h | 2998 +----------------------------------------- > > > > > > include/uapi/linux/pci_ids.h | 2997 +++++++++++++++++++++++++++++++++++++++++ > > > > > > > > > > No, please use the pci ids file from the upstream pci id database > > > > > instead. > > > > > > > > > > > > > We shouldn't be putting these all in one file, > > > > > > > > pci.txt says: > > > > Please add PCI_VENDOR_ID_xxx for vendors > > > > You want to change this policy, and get rid of > > > > vendor ids in pci_ids.h completely? > > > > > > Please read the top of pci_ids.h. It hasn't had new ids added to it in > > > a long time. > > > > OK, looks like pci.txt should be fixed then. > > Please send a patch. As the original PCI kernel maintainer, I don't > think I ever noticed pci.txt. It was last "updated" in 2006... > > > > Why would userspace need the pci id of anything? > > > > Look at how they are used e.g. by QEMU, seabios, gpxe. > > People want to say e.g. "find all network class devices". > > Then use libpci. > > > > Again, just use > > > libpci, isn't it fast enough? Don't duplicate existing logic. > > > > This really depends on whether you want something else that > > libpci provides. But if I just want e.g. standard class IDs, > > I don't want to depend on libpci. > > Why not? Don't duplicate things that already are there just for this > very use. > > Don't make us do kernel changes just because you don't want to depend on > either of the two different userspace packages that provide this > information in a standard way for userspace. Your system will have one > of those two packages in it, depending on it isn't a "burden" at all. > > > > Or use the hw database that libudev exports, which is already on your > > > machine and exports all of the pci ids from libpci directly. > > > > Same argument really. > > Because you don't want to depend on existing packages, doesn't mean we > have to accept kernel changes and maintain them for forever, as you are > now creating a new api that we will have to keep up to date and correct > for all time. > > Again, depend on the packages that are already doing this work please. > Maintaining correct class IDs is more or less a requirement for kernel to work properly, isn't it? Wouldn't the same thing apply to pci_regs.h? Why does it make sense to export PCI_CLASS_REVISION so I know where to read the class value from configuration, but not what the values are? > > > > Standard class IDs are even sillier to duplicate. > > > > > > Again, why does userspace need this? > > > > > > thanks, > > > > > > greg k-h > > > > Mostly because it has a userspace driver, or is emulating > > a hardware device. > > > > For example, the VFIO driver uses the PCI hardware formats > > as it's userspace/kernel interface. This means I need > > a ton of PCI constants in userspace. Most of them are > > already in pci_regs.h, and so exported. No problem here. > > > > However class and prog interface IDs are not, they > > are in pci_ids.h > > > > Would you support splitting pci_ids.h to > > include/uapi/linux/pci_ids.h with standard headers > > and include/linux/pci_ids.h with device/vendor > > specific ones? > > No, again, please use the "standard" Linux apis for these, don't > duplicate work and make people do more work over the long-term than is > needed. > > thanks, > > greg k-h What's the work you refer to? This is just hardware description it can't change and doesn't need to be maintained. -- MST