From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754859AbaJUE1a (ORCPT ); Tue, 21 Oct 2014 00:27:30 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:35322 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754841AbaJUE11 (ORCPT ); Tue, 21 Oct 2014 00:27:27 -0400 Message-ID: <5445E0AB.1090306@roeck-us.net> Date: Mon, 20 Oct 2014 21:27:23 -0700 From: Guenter Roeck User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: =?UTF-8?B?UGFsaSBSb2jDoXI=?= CC: Arnd Bergmann , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Steven Honeyman Subject: Re: [PATCH] i8k: Ignore temperature sensors which report invalid values References: <1413730014-30945-1-git-send-email-pali.rohar@gmail.com> <5443D519.1090408@roeck-us.net> <201410201846.00586@pali> In-Reply-To: <201410201846.00586@pali> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-CTCH-PVer: 0000001 X-CTCH-Spam: Unknown X-CTCH-VOD: Unknown X-CTCH-Flags: 0 X-CTCH-RefID: str=0001.0A020206.5445E0AE.0137,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 X-CTCH-Score: 0.000 X-CTCH-ScoreCust: 0.000 X-CTCH-Rules: C_4847, X-CTCH-SenderID: linux@roeck-us.net X-CTCH-SenderID-Flags: 0 X-CTCH-SenderID-TotalMessages: 2 X-CTCH-SenderID-TotalSpam: 0 X-CTCH-SenderID-TotalSuspected: 0 X-CTCH-SenderID-TotalConfirmed: 0 X-CTCH-SenderID-TotalBulk: 0 X-CTCH-SenderID-TotalVirus: 0 X-CTCH-SenderID-TotalRecipients: 0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: mailgid no entry from get_relayhosts_entry X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/20/2014 09:46 AM, Pali Rohár wrote: > Ok, I will describe my problem. Guenter, maybe you can find > another solution/fix for it. > > Calling i8k_get_temp(3) on my laptop without I8K_TEMPERATURE_BUG > always returns value 193 (which is above I8K_MAX_TEMP). > > When I8K_TEMPERATURE_BUG is enabled (by default) then > i8k_get_temp(3) returns value from prev[3] and store new value > I8K_TEMPERATURE_BUG to prev[3]. Value in prev[3] is initialized > to 0. > > What I want to achieve is: when i8k_get_temp() for particular > sensor id always returns invalid value (> I8K_MAX_TEMP) then we > should totally ignore sensor with that id and do not export it > via hwmon. > > My solution is: initialize prev[id] to I8K_MAX_TEMP, so on > invalid data first call to i8k_get_temp(id) returns I8K_MAX_TEMP. > Then in i8k_init_hwmon check if value is < I8K_MAX_TEMP and if > not ignore sensor id. > > Guenter, it is clear now? Are you ok that we should ignore sensor > if always report value above I8K_MAX_TEMP? If you do not like my > solution/patch for it, can you specify how other can it be fixed? > I still don't see the point in initializing prev[]. Yes, I am ok with ignoring sensor values if the reported temperature is above I8K_MAX_TEMP. I am just not sure if we should check against I8K_MAX_TEMP or against, say, 192. Reason is that we do know that the sensor can erroneously return 0x99 on some systems once in a while. We would not want to ignore those sensors just because they happen to report 0x99 during initialization. So maybe make it if (err >= 0 && err < 192) and add a note before the first if(), explaining that higher values suggest that there is no sensor attached. Thanks, Guenter > On Sunday 19 October 2014 17:13:29 Guenter Roeck wrote: >> On 10/19/2014 07:46 AM, Pali Rohár wrote: >>> On some machines some temperature sensors report too high >>> values which are >> >> What is "too high", and what is "some machines" ? >> Would be great if you can be more specific. >> >>> invalid. When value is invalid function i8k_get_temp() >>> returns previous value and at next call it returns >>> I8K_MAX_TEMP. >>> >>> With this patch also firt i8k_get_temp() call returns >>> I8K_MAX_TEMP and >> >> fix ? Also, I am not entirely sure I understand what exactly >> you are fixing here. >> >>> i8k_init_hwmon() will ignore all sensor ids which report >>> incorrect values. >>> >>> Signed-off-by: Pali Rohár >>> --- >>> >>> drivers/char/i8k.c | 10 +++++----- >>> 1 file changed, 5 insertions(+), 5 deletions(-) >>> >>> diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c >>> index 7272b08..bc327fa 100644 >>> --- a/drivers/char/i8k.c >>> +++ b/drivers/char/i8k.c >>> @@ -298,7 +298,7 @@ static int i8k_get_temp(int sensor) >>> >>> int temp; >>> >>> #ifdef I8K_TEMPERATURE_BUG >>> >>> - static int prev[4]; >>> + static int prev[4] = { I8K_MAX_TEMP, I8K_MAX_TEMP, >>> I8K_MAX_TEMP, I8K_MAX_TEMP }; >> >> I am not sure I understand what this change is expected to >> accomplish. Please explain. >> >>> #endif >>> >>> regs.ebx = sensor & 0xff; >>> rc = i8k_smm(®s); >>> >>> @@ -610,17 +610,17 @@ static int __init i8k_init_hwmon(void) >>> >>> /* CPU temperature attributes, if temperature reading is >>> OK */ err = i8k_get_temp(0); >>> >>> - if (err >= 0) >>> + if (err >= 0 && err < I8K_MAX_TEMP) >> >> I8K_MAX_TEMP is, at least in theory, a valid temperature, so >> this should be "<=". >> >> It would be important to understand what the "too high" >> temperature is to possibly be able to distinguish it from the >> buggy temperature that the code is trying to fix. >> >> Thanks, >> Guenter >> >>> i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP1; >>> >>> /* check for additional temperature sensors */ >>> err = i8k_get_temp(1); >>> >>> - if (err >= 0) >>> + if (err >= 0 && err < I8K_MAX_TEMP) >>> >>> i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP2; >>> >>> err = i8k_get_temp(2); >>> >>> - if (err >= 0) >>> + if (err >= 0 && err < I8K_MAX_TEMP) >>> >>> i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP3; >>> >>> err = i8k_get_temp(3); >>> >>> - if (err >= 0) >>> + if (err >= 0 && err < I8K_MAX_TEMP) >>> >>> i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP4; >>> >>> /* Left fan attributes, if left fan is present */ >