From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: RTC_DRV_CMOS can break userspace interface Date: Mon, 28 May 2007 03:16:22 +0100 Message-ID: <20070528021622.GA24517@srcf.ucam.org> References: <20070527190351.GA21387@srcf.ucam.org> <20070527233911.GA23491@srcf.ucam.org> <20070528003822.GA23759@srcf.ucam.org> <200705271844.54589.david-b@pacbell.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from cavan.codon.org.uk ([217.147.92.49]:34888 "EHLO vavatch.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751221AbXE1CQe (ORCPT ); Sun, 27 May 2007 22:16:34 -0400 Content-Disposition: inline In-Reply-To: <200705271844.54589.david-b@pacbell.net> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: David Brownell Cc: linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org On Sun, May 27, 2007 at 06:44:49PM -0700, David Brownell wrote: > On Sunday 27 May 2007, Matthew Garrett wrote: > > Actually, it seems to be worse than that - the PNP entry for my cmos > > clock doesn't appear to mention an irq, so the wakealarm entry doesn't > > work. I can happily wake it using the /proc/acpi/alarm interface. > > > > David, would you be happy with hardcoding the rtc-cmos IRQ to 8 on PCs > > if there's inadequate PNP information available? > > That would seem to naturally belong in the PNP code, yes? > > Agreed that it seems like it needs to be hardcoded somewhere. The PNP code is reporting what's in the tables - I'd be a bit surprised if it special-cased specific devices, but I guess there's an argument for that. All the other machines I've checked report an IRQ, so I guess Apple just didn't take much care in getting this right. As far as sanity checking goes - how about we check that the reported io ports are the legacy range, and if so hardcode the irq if the hardware hasn't reported one? I'd /hope/ that nobody has produced any hardware that that would break, but then, well. The strongest argument for it being safe is probably that the legacy RTC driver seems to hardcode this and hasn't obviously been breaking things. -- Matthew Garrett | mjg59@srcf.ucam.org