From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from www49.your-server.de ([213.133.104.49]:47737 "EHLO www49.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753596Ab0ARI6s (ORCPT ); Mon, 18 Jan 2010 03:58:48 -0500 Received: from [188.97.242.148] (helo=[192.168.1.22]) by www49.your-server.de with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.69) (envelope-from ) id 1NWnRf-0005dF-5k for linux-media@vger.kernel.org; Mon, 18 Jan 2010 09:58:47 +0100 Message-ID: <4B5422C2.5010203@motama.com> Date: Mon, 18 Jan 2010 09:58:42 +0100 From: Andreas Besse MIME-Version: 1.0 CC: linux-media@vger.kernel.org Subject: Re: Order of dvb devices References: <4B4F39BB.2060605@motama.com> <4B4F3FD5.5000603@motama.com> <829197381001140809p1b1af4a4v2678abbc4c41b9ec@mail.gmail.com> <201001160000.31965@orion.escape-edv.de> <1a297b361001151508h42d3a4c9wdbc09b6199319c2a@mail.gmail.com> In-Reply-To: <1a297b361001151508h42d3a4c9wdbc09b6199319c2a@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: unlisted-recipients:; (no To-header on input)@bombadil.infradead.org Sender: linux-media-owner@vger.kernel.org List-ID: Manu Abraham wrote: > On Sat, Jan 16, 2010 at 3:00 AM, Oliver Endriss wrote: > >> Devin Heitmueller wrote: >> >>> On Thu, Jan 14, 2010 at 11:01 AM, Andreas Besse wrote: >>> >>>> yes if there are different drivers I already observed the behaviour that >>>> the ordering gets flipped after reboot. >>>> >>>> But if I assume, that there is only *one* driver that is loaded (e.g. >>>> budget_av) for all dvb cards in the system, how is the ordering of these >>>> devices determined? How does the driver "search" for available dvb cards? >>>> >> The driver does not 'search' for a card. The driver registers the ids of >> all supported cards with the pci subsystem of the kernel. >> >> When the pci subsystem detects a new card, it calls the 'probe' routine >> of the driver (for example saa7146_init_one for saa7146-based cards). >> So the ordering is determined by the pci subsystem. >> >> >>> I believe your assumption is incorrect. I believe the enumeration >>> order is not deterministic even for multiple instances of the same >>> driver. It is not uncommon to hear mythtv users complain that "I have >>> two PVR-150 cards installed in my PC and the order sometimes get >>> reversed on reboot". >>> >> Afaik the indeterministic behaviour is caused by udev, not by the >> kernel. We never had these problems before udev was introduced. >> > > > True, the ordering is not exactly the same everytime. One will need to > provide PCI Bus related info also to a practical udev configuration to > get things sorted out in a sane way, rather than anything else. > with "PCI Bus related info" you mean the KERNELS parameter which is reported by udevinfo? udevinfo -a -p $(udevinfo -q path -n /dev/dvb/adapter0/frontend0) [...] looking at parent device '/devices/pci0000:00/0000:00:1e.0/0000:08:00.0': KERNELS=="0000:08:00.0" SUBSYSTEMS=="pci" does this KERNELS parameter always match the Slot-Id of "lspci -vmm" ? Slot: 08:00.0 Class: Multimedia controller Vendor: Philips Semiconductors Device: SAA7146 SVendor: Technotrend Systemtechnik GmbH SDevice: S2-3200 Rev: 01 is it right that the Slot-Id is deterministic for PCI/PCIe based systems?