From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brownell Date: Tue, 08 Oct 2002 17:02:59 +0000 Subject: Re: /sbin/hotplug invocation for USB devices in 2.5.40 Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-hotplug@vger.kernel.org Greg KH wrote: > As almost no one noticed, I changed the environment variables that > /sbin/hotplug is called with in 2.5.40 :) I look at it just a bit differently ... where previously it only issued calls for the first interface (typically that's all there is), now it issues calls for every interface, _plus_ a call for a new kind of thing never before seen through hotplug, a "usb device". I really like the "event for each interface" change, though I'd like it a bit better if we could tell this 2.5+ behavior apart from earlier ones -- so hotplug agents can act accordingly. Its that new type of hotplug event that makes recent kernels trigger syslog messages about "Bad USB agent invocation". > Now I know this overloads the existing DEVICE usage for USB devices, but > I think we can determine what do properly (basically just test for > DEVFS, and if it's not set, then we are looking at the driverfs entry > for the device.) I'd rather see these changes: - This new parameter to every (!!) hotplug event gets renamed to KFS_DEVICE (assuming that's the new driverfs name). Hotplug agents will need to access KFS data *and* talk to the device (and its drivers) using the DEVICE= path. Plus, if this is present we know we don't need to ask 'usbmodules' to scan other interfaces for us. (That often triggers other problems.) - Don't make hotplug calls for USB devices until we have something for them to do. (Essentially these are a new class of event.) The example that comes to mind is policy agents using those events to choose a non-default device configuration. But USB needs a bunch of work before such things become practical. I think both of those would be simple changes to make. They'd greatly improve backward compatibility, while letting us do better things on Linux Next Generation systems. > I also created a lot of individual driverfs files for the USB device, > basically everything that used to be specified by a environment variable > in the call to /sbin/hotplug, is now a value in a file. So ideally, we > can get rid of those other variables for the USB call, and just rely on > the info present in driverfs. That'd only work if both KFS_DEVICE and DEVICE are simultaneously available. See above ... :) I wouldn't de-support the other parameters for quite a while, though it's certainly good to have such improved flexibility. By the way, what's the cost of a driverfs attribute on a 'struct device'? Each USB device now has over a dozen of them. - Dave ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ 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