From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [PATCH] input: i8042: add quirk to implement i8042 detect for AMD Date: Sat, 17 Oct 2015 09:38:47 -0700 Message-ID: <20151017163847.GB13470@dtor-ws> References: <1445002020-12672-1-git-send-email-Vincent.Wan@amd.com> <20151016085808.GA32193@pd.tnic> <20151016102155.GD31612@pd.tnic> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pa0-f46.google.com ([209.85.220.46]:35194 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752154AbbJQQiv (ORCPT ); Sat, 17 Oct 2015 12:38:51 -0400 Content-Disposition: inline In-Reply-To: <20151016102155.GD31612@pd.tnic> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Borislav Petkov Cc: Wan ZongShun , Huang Rui , Vincent Wan , linux-input@vger.kernel.org, linux-kernel On Fri, Oct 16, 2015 at 12:21:55PM +0200, Borislav Petkov wrote: > On Fri, Oct 16, 2015 at 05:35:40PM +0800, Wan ZongShun wrote: > > 2015-10-16 16:58 GMT+08:00 Borislav Petkov : > > > On Fri, Oct 16, 2015 at 09:27:00AM -0400, Vincent Wan wrote: > > >> Detecting platform supports i8042 or not, AMD resorted to > > >> BIOS's FADT i8042 flag. > > >> > > >> Signed-off-by: Vincent Wan > > >> --- > > >> drivers/input/serio/i8042-x86ia64io.h | 6 ++++++ > > >> 1 file changed, 6 insertions(+) > > > > >> /* > > >> @@ -1047,6 +1048,11 @@ static int __init i8042_platform_init(void) > > >> /* Just return if pre-detection shows no i8042 controller exist */ > > >> if (!x86_platform.i8042_detect()) > > >> return -ENODEV; > > >> + > > >> + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) { > > > > > > Why the vendor check if you're accessing a bit defined in the ACPI spec? > > > > From intel's 'x86_platform.i8042_detect' implementation, I doubt if > > their BIOS is providing this i8024 flag. > > Why would you doubt that - it is at least in ACPI v4, if not earlier. If > you still doubt that, go and check it or ask Intel people. > > > So I have to implement my codes carefully. > > What are you people talking about?! > > It is in the ACPI spec - this bit is either set or not. If it is not Well, the fact that is is in a spec does not mean that vendors follow it (and BTW I do not think that AMD as a CPU vendor can vouch for a random notebook or desktop vendor that acquired and then hacked on some version of some BIOS from some BIOS vendor so I agree that this check is a no-go). Historically we did not trust BIOS data with regard to i8042 on x86. Maybe we should now using certain date cutoff (anything manufactured past 201[2345?]). Does Windows respect this flag? If it does then we could also trust it, and not only on AMD but for all x86 CPUs. Thanks. -- Dmitry