From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Date: Fri, 11 Mar 2005 06:45:59 +0000 Subject: Re: New hotplug interface is not working right for me Message-Id: <20050311064559.GA28379@kroah.com> List-Id: References: <20050311060405.GA16141@thyrsus.com> In-Reply-To: <20050311060405.GA16141@thyrsus.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-hotplug@vger.kernel.org On Fri, Mar 11, 2005 at 01:04:05AM -0500, Eric S. Raymond wrote: > Greg KH : > > On Fri, Mar 11, 2005 at 12:20:54AM -0500, Eric S. Raymond wrote: > > > Greg KH : > > > > > The problem appears to be that whatever thread of control is creating > > > > > the /dev/ttyUSB* node is running asynchronously with the hotplug > > > > > script and does not reliably (or even usually) create it before the > > > > > gpsd instance gets spawned and goes looking for the node. > > > > > > > > Then use the /etc/dev.d/ interface instead. That requires udev and a > > > > 2.6 kernel, but is the only way you can know exactly when the /dev entry > > > > is created. > > > > > > Where is this documented? > > > > In the udev documentation and a simple google search brings it up. > > > > > Even if the /etc/dev.d/ interface works, that doesn't really make it > > > acceptable that the /etc/hotplug.d/ interface is broken. There is some > > > locking that ought to be happening and isn't. > > > > The interface is not broken, you are trying to trigger off of two > > different hotplug events (one when the device appears, and a different > > one when the device node is to be created.) > > If it's not broken, then it's not documented either. You are watching for the wrong hotplug event, how can we document that? :) > Or, at least, I don't see any documentation that tells me about a > second hotplug event when /dev/ttyUSB0 is created. Now, if I could > write a script that would fire on only only /dev/ttyUSB* creation events and > allow me to filter on the vendor/product ID, that would be fine -- those > are what I'm really interested in. You can, just put your script into /etc/hotplug.d/tty and watch for the device name to be ttyUSB*. Then walk the sysfs chain back up the directory to see the vendor and product id of the device attached to that ttyUSB device. thanks, greg k-h ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_ide95&alloc_id396&op=click _______________________________________________ Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net Linux-hotplug-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel