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Message-ID: <Pine.LNX.4.44L0.1608251521480.1395-100000@iolanthe.rowland.org>
Date: Thu, 25 Aug 2016 15:35:49 -0400 (EDT)
From: Alan Stern <stern@...land.harvard.edu>
To: Jacek Anaszewski <jacek.anaszewski@...il.com>
cc: Jacek Anaszewski <j.anaszewski@...sung.com>,
Rafał Miłecki <zajec5@...il.com>,
Richard Purdie <rpurdie@...ys.net>,
Felipe Balbi <balbi@...nel.org>,
Greg KH <gregkh@...uxfoundation.org>,
Peter Chen <hzpeterchen@...il.com>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
Rafał Miłecki <rafal@...ecki.pl>,
Jonathan Corbet <corbet@....net>,
Ezequiel Garcia <ezequiel@...guardiasur.com.ar>,
Stephan Linz <linz@...pro.net>,
Matthias Brugger <mbrugger@...e.com>,
Boris Brezillon <boris.brezillon@...e-electrons.com>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
"open list:DOCUMENTATION" <linux-doc@...r.kernel.org>,
open list <linux-kernel@...r.kernel.org>,
"open list:LED SUBSYSTEM" <linux-leds@...r.kernel.org>,
Pavel Machek <pavel@....cz>
Subject: Re: [PATCH RFC V3.5] leds: trigger: Introduce an USB port trigger
On Thu, 25 Aug 2016, Jacek Anaszewski wrote:
> >>> 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.
> Is there a way to retrieve the corresponding names in kernel?
If the device provides the string descriptors then the textual product
and manufacturer files are available in sysfs, otherwise they aren't.
> Does the lsusb command do the mapping in the user space or maybe
> it takes the names from kernel?
lsusb does the mapping in userspace, based on an ID database. On my
system (Fedora), the database is /etc/udev/hwdb.bin.
Alan Stern
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