Date: Wed, 06 Aug 2014 08:20:24 +0200 From: Hans Petter Selasky <hps@selasky.org> To: Peter Losher <plosher@isc.org>, freebsd-usb@freebsd.org Cc: Dan Mahoney <dmahoney@isc.org> Subject: Re: Setting USB probe priority... Message-ID: <53E1C928.8040409@selasky.org> In-Reply-To: <336D77E7-2845-4F62-9627-75D442CCAB14@isc.org> References: <336D77E7-2845-4F62-9627-75D442CCAB14@isc.org>
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On 08/06/14 01:50, Peter Losher wrote: > (please include my and Dan's email in any responses as we normally don't lurk on the USB mailing list) > > So @work we use serial->USB TTY MUX's to handle our serial console needs, and at some sites we have a need that is greater than a single 16 port device (the max you can get). The problem is that with two of these 16 port USB devices is that sometimes during a reboot that the "second" device gets probed first and so the first 16 and second 16 /dev/ttyU* blocks swap around... which of course plays havoc with any symlinks we have to the devices in rtty or conserver. :( > > Is there any way to tell the USB code to always select a certain device first? I assume this has been a issue with USB storage devices so this shouldn't be a new issue. And I tried searching for a answer on the web to no avail. > > Ideas? Hi, USB enumerates in sequential order, but sometimes devices might not be ready to enumerate, and then a port is skipped. Does the device have a serial number? usbconfig -d X.Y dump_device_desc |grep iSerial If yes, this can be filtered by a devd rule, when the device attaches, and then you can switch the serial number to create any symbolic links. --HPS
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