From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752285AbaHVWsW (ORCPT ); Fri, 22 Aug 2014 18:48:22 -0400 Received: from mout.gmx.net ([212.227.15.19]:58541 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752138AbaHVWsV (ORCPT ); Fri, 22 Aug 2014 18:48:21 -0400 From: Peter =?iso-8859-1?q?H=FCwe?= To: Jason Gunthorpe Subject: Re: [PATCH] tpm_tis: Verify ACPI-specified interrupt Date: Sat, 23 Aug 2014 00:48:46 +0200 User-Agent: KMail/1.13.7 (Linux/3.16.0-rc7; KDE/4.12.5; x86_64; ; ) Cc: Scot Doyle , Ashley Lai , Marcel Selhorst , Stefan Berger , tpmdd-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, semenzato@google.com References: <20140822203241.GB1733@obsidianresearch.com> In-Reply-To: <20140822203241.GB1733@obsidianresearch.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201408230048.47293.PeterHuewe@gmx.de> X-Provags-ID: V03:K0:iaYVa8CIHVyAlmL+tbzK6WSqZCWKR0RL9JkUyL8wtzl33lyFR54 az2mGZ62ikFMqZZsTKfGrBu2cy+0uGNGv32gG/jpoMktOnpk3+c5UQ4xz4XT+Ot3g02an/Z WLkWMVsaZ5cWJC3sDwNano3xk4kgJu4ahuB+nRfI/9zrneOmZDVxIsTaijDBaYi/kdafGfX aBxOCHszbfrwq5HxuWwOg== X-UI-Out-Filterresults: notjunk:1; Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org CC: Luigi, he works at Google and is responsible for the TPMs in Chromebooks ;) Thanks, Peter Am Freitag, 22. August 2014, 22:32:41 schrieb Jason Gunthorpe: > On Fri, Aug 22, 2014 at 08:17:27PM +0000, Scot Doyle wrote: > > On Fri, 22 Aug 2014, Jason Gunthorpe wrote: > > > On Fri, Aug 22, 2014 at 12:58:41AM +0000, Scot Doyle wrote: > > >> Some machines, such as the Acer C720 and Toshiba CB35, have TPMs > > >> that do not use interrupts while also having an ACPI TPM entry > > > > > > How do these machines work in Windows? > > > > I don't know. Since they're Chromebooks (booted in legacy mode running > > SeaBIOS instead of depthcharge or whatever ChromeOS uses), I think > > they're mostly used to run Linux. > > I remain somewhat confused - there have already been TPM patches for > Chromebooks from Google - presumably the TPM actually does work > fine. Make sure you are using a Linux with the ATMEL timeout fix, that > is particularly applicable to Chromebooks IIRC. > > And again, the driver uses interrupts when booting, so I'm somewhat > confused what the problem is. I wouldn't think the driver would > successfully attach if interrupts were enabled but the interrupt > didn't work? Can you elaborate on what is going on during boot with > the interrupt, and the boot time GET_DURATIONS and TPM_STARTUP > sequences? > > Perhaps the driver is timing out all commands and going ahead and > attaching anyhow? If this is the case I think we'd get a good result > if we just fixed that and had the driver simply not attach. Then your > resume will not be broken. > > > > I'd be more comfortable with some kind of ACPI black list or patch or > > > something? What is normal for handling broken ACPI? > > > > I would be more comfortable with this general approach as well. However, > > I've had to submit several patches for individual Chromebooks related to > > backlight control since the VBT also is misconfigured. Would it be > > possible to find a blacklist mechanism that didn't require identifying > > each Chromebook separately, since they seem to have this issue on an > > ongoing basis? > > So, if you are booting the Chromebook in some weird way, is this a > problem that can be addressed by patching SeaBIOS instead of the > kernel? The internet says the SeaBIOS payload is replaceable on the > Chromebook. > > Can it fix the ACPI tables to be correct before lauching Linux? > > > A more general approach might be to verify the ACPI interrupt for > > systems matching the first three identifiers. > > Testing the interrupt and failing driver attach if it doesn't work > seems very reasonable to me, I would view that as a bug fix in the driver. > > Jason