Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759576AbaGRHOu (ORCPT ); Fri, 18 Jul 2014 03:14:50 -0400 Received: from mail-lb0-f182.google.com ([209.85.217.182]:58385 "EHLO mail-lb0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752175AbaGRHOr (ORCPT ); Fri, 18 Jul 2014 03:14:47 -0400 From: matwey@sai.msu.ru To: gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, linux-parport@lists.infradead.org, hsommer@eso.org, gnomes@lxorguk.ukuu.org.uk, matwey.kornilov@gmail.com, "Matwey V. Kornilov" Subject: [PATCHv4 0/2] parport: parport_pc: Fix false-positives at checking for Intel bug Date: Fri, 18 Jul 2014 11:12:53 +0400 Message-Id: <1405667575-3291-1-git-send-email-matwey@sai.msu.ru> X-Mailer: git-send-email 1.8.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Matwey V. Kornilov" Hi, The following patch series is to deal with the issue on false-positives of Intel EPP bug check [1]. More than a decade ago, the check was introduced in order to prevent EPP operation on the some Intel LPT chipsets. The main issue to defence from was CPU hang at EPP operation on broken chipsets. It is mentioned that affected chipsets are Intel 82091. However, it is not known whether there are others. The check was implemented in strange manner. Now, there is no explanations why. The check itself now leads to the false-positives, disabling EPP on many PC-s (Dell OptiPlex series for instance). The latter is an issue. As it was suggested by One Thousand Gnomes we implement the additional check of CPU model. If CPU is Intel 80486 or Pentium, then it is considered as potentially affected by the initial problem, so the initial check is applied. The patches organized as following: 1. Introduce-intel_bug_present-function. The transparent refactoring of the check is performed. Make the check be immutable regarding to ECR register. 2. Implement CPU model check to cut off false-positives Based on CPU model, disable the check. The check is enabled only for Intel 80486 or Pentium. [1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=630593 Suggested-by: One Thousand Gnomes Tested-by: Heiko Andreas Sommer Signed-off-by: Matwey V. Kornilov --- Changes from v3: - Do not introduce the additional option, rely on CPU model instead. Changes from v2: - The module option has more clear description Changes from v1: - Patch 1 fetched from right branch and now compiled -- 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/