Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759781AbaGRHOv (ORCPT ); Fri, 18 Jul 2014 03:14:51 -0400 Received: from mail-lb0-f172.google.com ([209.85.217.172]:65519 "EHLO mail-lb0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752750AbaGRHOt (ORCPT ); Fri, 18 Jul 2014 03:14:49 -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 2/2] parport: parport_pc: Implement CPU model check to cut off false-positives Date: Fri, 18 Jul 2014 11:12:55 +0400 Message-Id: <1405667575-3291-3-git-send-email-matwey@sai.msu.ru> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1405667575-3291-1-git-send-email-matwey@sai.msu.ru> References: <1405667575-3291-1-git-send-email-matwey@sai.msu.ru> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Matwey V. Kornilov" The code in intel_bug_present is known to produce much false-positives. It is believed that the affected by the bug hardware are used with either Intel 80486 or Pentium. Perform the check only when the kernel configured as CONFIG_X86_32, then use cpuinfo_x86 of the first available CPU to check the model and run initial check code. Suggested-by: One Thousand Gnomes Tested-by: Heiko Andreas Sommer Signed-off-by: Matwey V. Kornilov --- drivers/parport/parport_pc.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/drivers/parport/parport_pc.c b/drivers/parport/parport_pc.c index a6eaafb..6b28f9f 100644 --- a/drivers/parport/parport_pc.c +++ b/drivers/parport/parport_pc.c @@ -65,6 +65,7 @@ #include #include #include +#include #define PARPORT_PC_MAX_PORTS PARPORT_MAX @@ -1702,7 +1703,11 @@ static int parport_ECP_supported(struct parport *pb) } #endif -static int intel_bug_present(struct parport *pb) +/* It is believed that CPU model correlates with buggy LPT chipset model. + Here we check that or CPU is elder than Pentium Pro: either 80486 or Pentium. + If it is then we perform The Check. */ +#ifdef CONFIG_X86_32 +static int intel_bug_present_check_epp(struct parport *pb) { const struct parport_pc_private *priv = pb->private_data; int bug_present = 0; @@ -1725,6 +1730,20 @@ static int intel_bug_present(struct parport *pb) return bug_present; } +static int intel_bug_present(struct parport *pb) +{ + struct cpuinfo_x86 *c = &cpu_data(0); + + if (c->x86_vendor == X86_VENDOR_INTEL && (c->x86 == 4 || c->x86 == 5)) + return intel_bug_present_check_epp(pb); + return 0; +} +#else +static int intel_bug_present(struct parport *pb) +{ + return 0; +} +#endif static int parport_ECPPS2_supported(struct parport *pb) { -- 1.8.1.4 -- 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/