From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCH RFC V3.5] leds: trigger: Introduce an USB port trigger Date: Fri, 26 Aug 2016 21:50:34 +0200 Message-ID: <20160826195034.GC21442@amd> References: <57BF3D64.3090402@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <57BF3D64.3090402@gmail.com> Sender: linux-doc-owner@vger.kernel.org To: Jacek Anaszewski Cc: Alan Stern , Jacek Anaszewski , =?utf-8?B?UmFmYcWCIE1pxYJlY2tp?= , Richard Purdie , Felipe Balbi , Greg KH , Peter Chen , "linux-usb@vger.kernel.org" , =?utf-8?B?UmFmYcWCIE1pxYJlY2tp?= , Jonathan Corbet , Ezequiel Garcia , Stephan Linz , Matthias Brugger , Boris Brezillon , Geert Uytterhoeven , "open list:DOCUMENTATION" , open list , open list:LED SUBSYST List-Id: linux-leds@vger.kernel.org On Thu 2016-08-25 20:48:04, Jacek Anaszewski wrote: > On 08/25/2016 04:30 PM, Alan Stern wrote: > >On Thu, 25 Aug 2016, Jacek Anaszewski wrote: > > > >>I'd see it as follows: > >> > >>#cat available_ports > >>#1-1 1-2 2-1 > >> > >>#echo "1-1" > new_port > >> > >>#cat observed_ports > >>#1-1 > >> > >>#echo "2-1" > new_port > >> > >>#cat observed_ports > >>#1-1 2-1 > >> > >>We've already had few discussions about the sysfs designs trying > >>to break the one-value-per-file rule for LED class device, and > >>there was always strong resistance against. > > > >This scheme has multiple values in both the available_ports and > >observed_ports files. :-( Not that I have any better suggestions... > > Right, I forgot to add a note here, that this follows space > separated list pattern similarly as in case of triggers attribute. > Of course other suggestions are welcome. > > >>>>Also a description of the device connected to the port would be a nice > >>>>feature, however I am not certain about the feasibility thereof. > >>> > >>>What kind of description do you mean? Where should it be used / where > >>>should it appear? > >>> > >> > >>Product name/symbol. Actually it should be USB subsystem responsibility > >>to provide the means for querying the product name by port id, if it > >>is possible at all. > > > > cat /sys/bus/usb/devices/PORT/product > > cat /sys/bus/usb/devices/PORT/manufacturer > > > >These will work if there is a device registered under PORT. > > I've found only idProduct and idVendor files. They indeed uniquely > identify the device, but the numbers are not human readable. Actually, they don't. They identify device _type_. If you have two mice of the same type connected, they'll have same idProduct / idVendor values. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html