From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: [PATCH] samsung-laptop: Disable if CONFIG_EFI=y Date: Mon, 5 Nov 2012 11:37:53 +0100 Message-ID: <20121105103753.GA25850@kroah.com> References: <1352050506-29317-1-git-send-email-matt@console-pimps.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1352050506-29317-1-git-send-email-matt@console-pimps.org> Sender: platform-driver-x86-owner@vger.kernel.org To: Matt Fleming Cc: Corentin Chary , Matthew Garrett , linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org, Alessandro Crismani , Mikhail Bakhterev , Patrick H , Matt Fleming , "H. Peter Anvin" , stable@vger.kernel.org List-Id: linux-efi@vger.kernel.org On Sun, Nov 04, 2012 at 05:35:06PM +0000, Matt Fleming wrote: > From: Matt Fleming > > We've started getting reports of users seeing Machine Check Exceptions > when booting their Samsung laptops in UEFI mode, > > https://bugzilla.kernel.org/show_bug.cgi?id=47121 > > This module seems to be the culprit as it's grovelling around in the > 0xf0000 region which has no mapping in either the e820 or EFI memory > maps on the affected machines. So, does this mean that if we try to ioremap a memory location in the kernel, like this driver is, it will not fail, but, when accessing the memory, bad things happen? That's not good, shouldn't the call to ioremap_nocache() have failed originally? That sounds like a core EFI/platform bug here, and one that you might run into other places. Shouldn't fixing that be the real fix? thanks, greg k-h