From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andreas Schwab Subject: Re: [PATCH] Fix hid_device_id for cross compiling Date: Thu, 30 Oct 2008 10:19:51 +0100 Message-ID: References: <20081030002332.4ef1fac4.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20081030002332.4ef1fac4.akpm@linux-foundation.org> (Andrew Morton's message of "Thu, 30 Oct 2008 00:23:32 -0700") Sender: linux-kernel-owner@vger.kernel.org To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-input@ver.kernel.org List-Id: linux-input@vger.kernel.org Andrew Morton writes: > On Sun, 26 Oct 2008 00:30:18 +0200 Andreas Schwab wr= ote: > >> struct hid_device_id contains hidden padding which is bad for cross >> compiling. Make the padding explicit and consistent across >> architectures. >>=20 > > What is "bad" about it? It is bad because it depends on the alignment restrictions of the architecture. On m68k everything is aligned on a 2-byte boundary, so this padding does not exist. > Can you expand a bit on the problem which is being fixed here? It's the well known cross compiling problem with modpost that has bitte= n us so often before. This one is even worse, because modpost would silently read bogus values since the struct size is the same, only the padding moves elsewhere. Andreas. --=20 Andreas Schwab, SuSE Labs, schwab@suse.de SuSE Linux Products GmbH, Maxfeldstra=DFe 5, 90409 N=FCrnberg, Germany PGP key fingerprint =3D 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4= ED5 "And now for something completely different."