From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752190AbaK3JAE (ORCPT ); Sun, 30 Nov 2014 04:00:04 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:50382 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751918AbaK3JAC (ORCPT ); Sun, 30 Nov 2014 04:00:02 -0500 Message-ID: <547ADC90.8000507@roeck-us.net> Date: Sun, 30 Nov 2014 01:00:00 -0800 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=?= , Arnd Bergmann , Greg Kroah-Hartman CC: Steven Honeyman , linux-kernel@vger.kernel.org Subject: Re: [PATCH] i8k: Fix temperature bug handling in i8k_get_temp() References: <201411181546.51284@pali> <1416322614-10308-1-git-send-email-pali.rohar@gmail.com> In-Reply-To: <1416322614-10308-1-git-send-email-pali.rohar@gmail.com> 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=0001.0A02020A.547ADC91.00DB,ss=1,re=0.001,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 X-CTCH-Score: 0.001 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: 1 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 11/18/2014 06:56 AM, Pali Rohár wrote: > Static array prev[] was incorrectly initialized. It should be initialized to > some "invalid" temperature value (above I8K_MAX_TEMP). > > Next, function should store "invalid" value to prev[] (above I8K_MAX_TEMP), > not valid (= I8K_MAX_TEMP) because whole temperature bug handling will not > work. > > And last part, to not break existing detection of temperature sensors, register > them also if i8k report too high temperature (above I8K_MAX_TEMP). This is > needed because some sensors are sometimes turned off (e.g sensor on GPU which > can be turned off/on) and in this case SMM report too high value. > > To prevent reporting "invalid" values to userspace, return -EINVAL. In this case > sensors which are currently turned off (e.g optimus/powerexpress/enduro gpu) > are reported as "N/A" by lm-sensors package. > > Signed-off-by: Pali Rohár > --- > drivers/char/i8k.c | 16 ++++++++++------ > 1 file changed, 10 insertions(+), 6 deletions(-) > > diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c > index 7272b08..e34a019 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+1, I8K_MAX_TEMP+1, I8K_MAX_TEMP+1, I8K_MAX_TEMP+1 }; > #endif > regs.ebx = sensor & 0xff; > rc = i8k_smm(®s); > @@ -317,10 +317,12 @@ static int i8k_get_temp(int sensor) > */ > if (temp > I8K_MAX_TEMP) { > temp = prev[sensor]; > - prev[sensor] = I8K_MAX_TEMP; > + prev[sensor] = I8K_MAX_TEMP+1; > } else { > prev[sensor] = temp; > } > + if (temp > I8K_MAX_TEMP) > + return -ERANGE; Can we return -ENODATA in this case ? I think that would be more appropriate. > #endif > > return temp; > @@ -499,6 +501,8 @@ static ssize_t i8k_hwmon_show_temp(struct device *dev, > int temp; > > temp = i8k_get_temp(index); > + if (temp == -ERANGE) > + return -EINVAL; and can we also return -ENODATA to user space ? This would make the code a bit cleaner. Thanks, Guenter