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From: Martin Mares <mj@ucw.cz>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Jonathan Corbet <corbet@lwn.net>,
	"David S. Miller" <davem@davemloft.net>,
	Hans Verkuil <hans.verkuil@cisco.com>,
	Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
	Alexei Starovoitov <ast@plumgrid.com>,
	stephen hemminger <stephen@networkplumber.org>,
	Masahiro Yamada <yamada.m@jp.panasonic.com>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	linux-api@vger.kernel.org, Greg KH <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v2] pci: export class IDs from pci_ids.h
Date: Tue, 7 Apr 2015 14:57:19 +0200	[thread overview]
Message-ID: <mj+md-20150407.125023.43354.nikam@ucw.cz> (raw)
In-Reply-To: <20150405132041-mutt-send-email-mst@redhat.com>

Hello!

> That's a good idea. Martin, could you please answer the following:
> assuming that linux exported linux/pci_ids.h providing class
> IDs that are currently in /usr/include/pci/header.h
> in a header /usr/include/linux/pci_ids.h,
> would libpci be open to replacing part of
> /usr/include/pci/header.h with #include <linux/pci_ids.h>,
> assuming that a solution for old systems that lack this
> header is also provided?

Please remember that libpci is cross-platform. Your proposal would make it
use <linux/pci_ids.h> on Linux and provide its own definitions on all other
systems, which is likely to bring less consistency, not more.

I do not see any point in using kernel headers for things, which are unrelated
to the kernel.

> pciutils does nothing with this value itself, it's possible for a distro
> to ship a wrong header, and no one will notice. OTOH Linux will break if
> it's wrong.  In fact there are 3 values libpci does appear to use
> internally:
> PCI_CLASS_BRIDGE_HOST
> PCI_CLASS_DISPLAY_VGA
> PCI_CLASS_BRIDGE_PCI
> 
> I'm guessing others are re-exported for the benefit of
> applications using libpci.

Exactly. And I expect that it will be quite similar with the kernel --
most classes defined in <linux/pci_ids.h> are not likely to be used anywhere
in the kernel.

				Martin

WARNING: multiple messages have this Message-ID (diff)
From: Martin Mares <mj-+ZI9xUNit7I@public.gmane.org>
To: "Michael S. Tsirkin" <mst-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Bjorn Helgaas <bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
	"linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Jonathan Corbet <corbet-T1hC0tSOHrs@public.gmane.org>,
	"David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>,
	Hans Verkuil
	<hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>,
	Mauro Carvalho Chehab
	<mchehab-JPH+aEBZ4P+UEJcrhfAQsw@public.gmane.org>,
	Alexei Starovoitov <ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>,
	stephen hemminger
	<stephen-OTpzqLSitTUnbdJkjeBofR2eb7JE58TQ@public.gmane.org>,
	Masahiro Yamada
	<yamada.m-NAum8xwdG0+S7A1Ibl2khg@public.gmane.org>,
	"linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Greg KH
	<gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
Subject: Re: [PATCH v2] pci: export class IDs from pci_ids.h
Date: Tue, 7 Apr 2015 14:57:19 +0200	[thread overview]
Message-ID: <mj+md-20150407.125023.43354.nikam@ucw.cz> (raw)
In-Reply-To: <20150405132041-mutt-send-email-mst-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

Hello!

> That's a good idea. Martin, could you please answer the following:
> assuming that linux exported linux/pci_ids.h providing class
> IDs that are currently in /usr/include/pci/header.h
> in a header /usr/include/linux/pci_ids.h,
> would libpci be open to replacing part of
> /usr/include/pci/header.h with #include <linux/pci_ids.h>,
> assuming that a solution for old systems that lack this
> header is also provided?

Please remember that libpci is cross-platform. Your proposal would make it
use <linux/pci_ids.h> on Linux and provide its own definitions on all other
systems, which is likely to bring less consistency, not more.

I do not see any point in using kernel headers for things, which are unrelated
to the kernel.

> pciutils does nothing with this value itself, it's possible for a distro
> to ship a wrong header, and no one will notice. OTOH Linux will break if
> it's wrong.  In fact there are 3 values libpci does appear to use
> internally:
> PCI_CLASS_BRIDGE_HOST
> PCI_CLASS_DISPLAY_VGA
> PCI_CLASS_BRIDGE_PCI
> 
> I'm guessing others are re-exported for the benefit of
> applications using libpci.

Exactly. And I expect that it will be quite similar with the kernel --
most classes defined in <linux/pci_ids.h> are not likely to be used anywhere
in the kernel.

				Martin

  reply	other threads:[~2015-04-07 13:04 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-30 11:33 [PATCH v2] pci: export class IDs from pci_ids.h Michael S. Tsirkin
2015-04-02 20:53 ` Bjorn Helgaas
2015-04-02 21:28   ` Michael S. Tsirkin
2015-04-02 21:59     ` Greg KH
2015-04-05 11:20       ` Michael S. Tsirkin
2015-04-02 22:32     ` Bjorn Helgaas
2015-04-05 12:05       ` Michael S. Tsirkin
2015-04-05 12:05         ` Michael S. Tsirkin
2015-04-07 12:57         ` Martin Mares [this message]
2015-04-07 12:57           ` Martin Mares

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