On Thu, Nov 07, 2002 at 12:23:50PM -0800, David Brownell wrote: > >>As well as updating some internal docs so they're current, > >>this patch adds the physical path to the data available > >>through hotplugging. This feature was requested at the > >>LinuxKongress hotplug BOF, and was also on my 2.5 list. > > > > > >And is already present with the DEVPATH environment variable, right? > > No, DEVPATH isn't as stable as the physical path. And will > not be available on 2.4 ... which will be important for a > few years yet, particularly for layers above the kernel.
Ok, but this was a patch for 2.5, right? We have DEVPATH, and don't need to have USB_PATH for 2.5. > Plus, you were at pains to explain to me how DEVPATH should > not be perceived as a physical path. They don't even try to > address the same problems. Sure, but what is the problem? It's as stable as what you are trying to use, right? > Here's part of what I got from hotplugging one keyboard: > > DEVICE=/proc/bus/usb/001/006 > ACTION=add > TYPE=9/0/0 > USB_PATH=usb-02:00.0-1.4 > DEVPATH=root/pci0/00:03.0/02:00.0/usb1/1-1/1-1.4/1-1.4:0 > PRODUCT=58f/9213/101 > > At best, DEVPATH needs a _lot_ of mangling to turn into > the physical ID. And using long IDs is always error prone. But the last file in DEVPATH is equal to what you wanted to use in USB_PATH, right? And if you really wanted the pci id, it's there too. > At worst, remember that identifiers like "pci0" and "usb1" > change a lot more readily than "02:00.0". (Even on cardbus > and similar hotplug pci, since most people have control over > which slots they use.) Using DEVPATH would ensure that > many more "should-be-minor" changes in system config will > need sysadmin and tool attention. That's generally not-good, > particularly when needs for routine tool use are so easy to > avoid ... save tool work for the important stuff! But I don't want to drag around two naming schemes for devices, let's stick to the one the rest of the kernel is going to use, DEVPATH. > If nothing else, think of it as a useful stable short > identifier ... you were the one who disliked the very > long driverfs paths, yes? :) Yes, but it's necessary :) I do like your comment cleanups, if you want to send me that part of the patch again. thanks, greg k-h ------------------------------------------------------- This sf.net email is sponsored by: See the NEW Palm Tungsten T handheld. Power & Color in a compact size! http://ads.sourceforge.net/cgi-bin/redirect.pl?palm0001en _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
