From patchwork Fri Nov 16 08:45:50 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Alex Hung X-Patchwork-Id: 998794 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=fwts-devel-bounces@lists.ubuntu.com; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=canonical.com Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 42xBf13rr4z9s8F; Fri, 16 Nov 2018 19:46:01 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1gNZlE-0002Xi-JE; Fri, 16 Nov 2018 08:45:56 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:128) (Exim 4.86_2) (envelope-from ) id 1gNZlC-0002Xa-U3 for fwts-devel@lists.ubuntu.com; Fri, 16 Nov 2018 08:45:54 +0000 Received: from 1.general.alexhung.us.vpn ([10.172.65.254] helo=canonical.com) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1gNZlC-0007bc-5L; Fri, 16 Nov 2018 08:45:54 +0000 From: Alex Hung To: fwts-devel@lists.ubuntu.com Subject: [PATCH] mtrr: allow uncached type for PCI prefetchable memory Date: Fri, 16 Nov 2018 16:45:50 +0800 Message-Id: <20181116084550.17167-1-alex.hung@canonical.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-BeenThere: fwts-devel@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Firmware Test Suite Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: fwts-devel-bounces@lists.ubuntu.com Sender: "fwts-devel" Buglink: https://bugs.launchpad.net/bugs/1781920 Intel® 64 and IA-32 Architectures Software Developer's Manual seems to suggest uncachable memory can be used for memory-mapped I/O. Details can be found in Section 11.3.2 - Choosing a Memory Type Signed-off-by: Alex Hung Acked-by: Colin Ian King Acked-by: Ivan Hu --- src/bios/mtrr/mtrr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/bios/mtrr/mtrr.c b/src/bios/mtrr/mtrr.c index 4948b55a..a614ffbb 100644 --- a/src/bios/mtrr/mtrr.c +++ b/src/bios/mtrr/mtrr.c @@ -351,7 +351,7 @@ static int guess_cache_type( if (pref) { *must = 0; - *mustnot = WRITE_BACK | UNCACHED; + *mustnot = WRITE_BACK; } else { *must = UNCACHED; *mustnot = (~UNCACHED) & (~DEFAULT);