Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754046AbbLATvX (ORCPT ); Tue, 1 Dec 2015 14:51:23 -0500 Received: from quartz.orcorp.ca ([184.70.90.242]:60425 "EHLO quartz.orcorp.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750894AbbLATvW (ORCPT ); Tue, 1 Dec 2015 14:51:22 -0500 Date: Tue, 1 Dec 2015 12:51:14 -0700 From: Jason Gunthorpe To: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Cc: Jarkko Sakkinen , tpmdd-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Martin Wilck , Peter Huewe Subject: Re: [PATCH v2 3/3] tpm_tis: Clean up the force=1 module parameter Message-ID: <20151201195114.GC16123@obsidianresearch.com> References: <1448996309-15220-1-git-send-email-jgunthorpe@obsidianresearch.com> <1448996309-15220-4-git-send-email-jgunthorpe@obsidianresearch.com> <20151201193358.GF5072@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20151201193358.GF5072@pengutronix.de> User-Agent: Mutt/1.5.23 (2014-03-12) X-Broken-Reverse-DNS: no host name found for IP address 10.0.0.160 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1688 Lines: 41 On Tue, Dec 01, 2015 at 08:33:58PM +0100, Uwe Kleine-K?nig wrote: > Hello, > > On Tue, Dec 01, 2015 at 11:58:29AM -0700, Jason Gunthorpe wrote: > > The TPM core has long assumed that every device has a driver attached, > > however commit b8b2c7d845d5 ("base/platform: assert that dev_pm_domain > > callbacks are called unconditionally") breaks that assumption. > > you asked for an alternative wording here. What about: > > The TPM core has long assumed that every device has a driver > attached, which is not valid. But it is valid, it is an invariant of the tpm core that a driver be attached, and prior to 'b8b that has been satisfied. > This was noticed with commit > b8b2c7d845d5 ("base/platform: assert that dev_pm_domain > callbacks are called unconditionally") which made probing of the > tpm_tis device fail by mistake and resulted in an oops later on. The probe didn't fail, the 'b8b causes a NULL probe function to result in no driver being attached. How about: The TPM has for a long time required that every device it uses has an attached driver. In the force case the tpm_tis driver met this via platform_register_simple and a NULL probe function for the driver. However, commit b8b2c7d845d5 ("base/platform: assert that dev_pm_domain callbacks are called unconditionally") causes NULL probe functions to no longer bind a driver. Did we ever reach a conclusion if Martin's patch should go ahead? Jason -- 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/