From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com (mx1.redhat.com [172.16.48.31]) by int-mx1.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n0FMtS3p012860 for ; Thu, 15 Jan 2009 17:55:28 -0500 Received: from dd18532.kasserver.com (dd18532.kasserver.com [85.13.139.13]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id n0FMtD08007081 for ; Thu, 15 Jan 2009 17:55:13 -0500 Date: Thu, 15 Jan 2009 23:55:11 +0100 From: Carsten Meier To: =?UTF-8?B?UMOhZHJhaWc=?= Brady Message-ID: <20090115235511.1ea5fdd5@tuvok> In-Reply-To: <496FB713.5020609@draigBrady.com> References: <20090115163348.5da9932a@tuvok> <09CD2F1A09A6ED498A24D850EB10120817E30B7506@Colmatec004.COLMATEC.INT> <20090115175121.25c4bdaa@tuvok> <496FB713.5020609@draigBrady.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: video4linux-list@redhat.com Subject: Re: How to identify USB-video-devices List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: video4linux-list-bounces@redhat.com Errors-To: video4linux-list-bounces@redhat.com List-ID: Am Thu, 15 Jan 2009 22:22:11 +0000 schrieb Pádraig Brady : > Carsten Meier wrote: > > Storing device-file-names is also not an option because they are > > created dynamicly. > > You use udev rules to give persistent names. > > Here is my /etc/udev/rules.d/video.rules file, > which creates /dev/webcam and /dev/tvtuner as appropriate. > > KERNEL=="video*" SYSFS{name}=="USB2.0 Camera", NAME="video%n", > SYMLINK+="webcam" KERNEL=="video*" SYSFS{name}=="em28xx*", > NAME="video%n", SYMLINK+="tvtuner" > > To find distinguishing attributes to match on use: > > echo /sys/class/video4linux/video* | xargs -n1 udevinfo -a -p > > cheers, > Pádraig. This already came up on the pvrusb2-list and someone told me (I don't know much about udev) that it might cause problems on disconnection of a device with a file-descriptor open which then gets reconnected and there are two device-files for it. I also don't like it, because an average user (including me) usually can't or don't want to write udev rules. Finally v4l2 already contains a very simple and reliable mechanism for doing this (bus_info-field) which simply isn't used correctly by the USB-drivers. My app should simply scan for /dev/video*-files, read out capabilities from them, present the user menus to select devices and edit device settings, save settings to a file and apply them on demand. This would work fine if bus_info was filled right, without root-privileges, without special udev rules or other sysfs-magic. Regards, Carsten -- video4linux-list mailing list Unsubscribe mailto:video4linux-list-request@redhat.com?subject=unsubscribe https://www.redhat.com/mailman/listinfo/video4linux-list