From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932755AbcFLLtJ (ORCPT ); Sun, 12 Jun 2016 07:49:09 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:34459 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932096AbcFLLtI (ORCPT ); Sun, 12 Jun 2016 07:49:08 -0400 Date: Sun, 12 Jun 2016 13:49:02 +0200 From: Ingo Molnar To: Lukas Wunner Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Bjorn Helgaas , Yinghai Lu , Matt Fleming , Linus Torvalds , Andrew Morton , Thomas Gleixner , "H. Peter Anvin" Subject: Re: [PATCH v2 3/3] x86/quirks: Add early quirk to reset Apple AirPort card Message-ID: <20160612114902.GA15940@gmail.com> References: <48d0972ac82a53d460e5fce77a07b2560db95203.1465690253.git.lukas@wunner.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <48d0972ac82a53d460e5fce77a07b2560db95203.1465690253.git.lukas@wunner.de> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Lukas Wunner wrote: > The solution is to reset the card on boot by writing to a reset bit in > its mmio space. This must be done as an early quirk and not as a plain > vanilla PCI quirk to successfully combat memory corruption by DMAed > packets: Matthew Garrett found out in 2012 that the packets are written > to EfiBootServicesData memory (http://mjg59.dreamwidth.org/11235.html). > This type of memory is made available to the page allocator by > efi_free_boot_services(). [...] Btw., would it also make sense to *not* free those pages by default, if firmware can occasionally corrupt them? What memory size are we talking about? Thanks, Ingo