Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761603Ab2ELAoU (ORCPT ); Fri, 11 May 2012 20:44:20 -0400 Received: from mail-yx0-f174.google.com ([209.85.213.174]:59388 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754890Ab2ELAoS (ORCPT ); Fri, 11 May 2012 20:44:18 -0400 Date: Fri, 11 May 2012 19:44:10 -0500 From: Jonathan Nieder To: Nestor Lopez Casado Cc: Jiri Kosina , Benjamin Tissoires , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, hugo@osvaldobarrera.com.ar, 671292@bugs.debian.org, stable@vger.kernel.org Subject: Re: [PATCH v2 1/1] HID: logitech: read all 32 bits of report type bitfield Message-ID: <20120512004410.GB2931@burratino> References: <1336745836-17385-1-git-send-email-nlopezcasad@logitech.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1336745836-17385-1-git-send-email-nlopezcasad@logitech.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1612 Lines: 37 Nestor Lopez Casado wrote: > From: Jonathan Nieder > > On big-endian systems (e.g., Apple PowerBook), trying to use a > logitech wireless mouse with the Logitech Unifying Receiver does not > work with v3.2 and later kernels. The device doesn't show up in > /dev/input. Older kernels work fine. > > That is because the new hid-logitech-dj driver claims the device. The > device arrival notification appears: > > 20 00 41 02 00 00 00 00 00 00 00 00 00 00 00 > > and we read the report_types bitfield (02 00 00 00) to find out what > kind of device it is. Unfortunately the driver only reads the first 8 > bits and treats that value as a 32-bit little-endian number, so on a > powerpc the report type seems to be 0x02000000 and is not recognized. Sigh, I took the wrong line in this example. The above event is "device list empty" and report_types is 0 as you'd expect. The example I meant to use: 20 01 41 01 1a 10 04 00 00 00 00 00 00 00 00 and we read the report_types bitfield (04 00 00 00) to find out what kind of device it is. Unfortunately the driver only reads the first 8 bits and treats that value as a 32-bit little-endian number, so on a powerpc the report type seems to be 0x04000000 and is not recognized. Jiri, please amend the message if convenient, or I'm fine with leaving it be if not. Sorry for the nonsense. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/