From mboxrd@z Thu Jan  1 00:00:00 1970
From: Matthias Schwarzott <zzam@gentoo.org>
Date: Wed, 02 May 2007 12:36:48 +0000
Subject: Re: udev problem DVB-S/T Cards
Message-Id: <200705021436.48314.zzam@gentoo.org>
List-Id: <linux-hotplug.vger.kernel.org>
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To: linux-hotplug@vger.kernel.org

On Samstag, 28. April 2007, Razza wrote:
> All,
> I have been playing with udev as I need to pin specific identical DVB cards
> to specific nodes, mixing DVB-S and DVB-T is bad!
> I have found how to identify cards etc. but getting the rule right is
> confusing me. I am running Fedora Core 5 and have the following standard
> rule in "/etc/udev/rules.d/50-udev.rules" -
>
> SUBSYSTEM="dvb", PROGRAM="/bin/sh -c 'K=%k; K=$${K#dvb}; printf
> dvb/adapter%%i/%%s $${K%%%%.*} $${K#*.}'", NAME="%c", MODE="0660"
>
Some time ago I also tried this. But it will end up like persistent-net then. 
You need good criteria to name the devices. Else it will only be chaos.
And most apps does not work with holes in the numbering as they just open 
devices starting from 0, until open fails.

Example:

Having /dev/dvb0/ /dev/dvb1/ /dev/dvb2/ and then unplugging the device 
formerly named dvb1. then you stay with devices dvb0 and dvb2.

The rule I would simply split into some more lines like:


SUBSYSTEM!="dvb", GOTO="dvb_end"
ACTION!="add", GOTO="dvb_end"

GROUP="video"
import{PROGRAM}="/bin/sh -c 'K=%k; K=$${K#dvb}; echo 
ID_DVB_ADAPTER_KERNEL=$${K%%%%.*}; echo ID_DVB_DEVICE=$${K#*.}'"

IMPORT{program}="path_id %p"

#Here set ID_DVB_ADAPTER to be persistent
# example:
ENV{ID_PATH}="pci-0000:00:0b.0-", ENV{ID_DVB_ADAPTER}="0"
ENV{ID_PATH}="pci-0000:00:0a.0-", ENV{ID_DVB_ADAPTER}="1"

# fallback-number
ENV{ID_DVB_ADAPTER_KERNEL}="?*", ENV{ID_DVB_ADAPTER}!="?*", 
ENV{ID_DVB_ADAPTER}="$env{ID_DVB_ADAPTER_KERNEL}"

# Create device
ENV{ID_DVB_ADAPTER}="?*", ENV{ID_DVB_DEVICE}="?*", 
NAME="dvb/adapter$env{ID_DVB_ADAPTER}/$env{ID_DVB_DEVICE}"


LABEL="dvb_end"

But this is untested.

The same problem will appear with all other devices being just numbered, like 
video and audio devices.

The simplest solution is to just blacklist the drivers from autoloading, and 
then load them in predefined/known order.

Matthias

-- 
Matthias Schwarzott (zzam)

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