From owner-svn-src-head@freebsd.org Mon May 23 19:32:26 2016 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 96E0DB46019; Mon, 23 May 2016 19:32:26 +0000 (UTC) (envelope-from rpokala@mac.com) Received: from mr11p00im-asmtp004.me.com (mr11p00im-asmtp004.me.com [17.110.69.135]) (using TLSv1.2 with cipher DHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 788BE18DE; Mon, 23 May 2016 19:32:26 +0000 (UTC) (envelope-from rpokala@mac.com) Received: from process-dkim-sign-daemon.mr11p00im-asmtp004.me.com by mr11p00im-asmtp004.me.com (Oracle Communications Messaging Server 7.0.5.36.0 64bit (built Sep 8 2015)) id <0O7N00500A3MDS00@mr11p00im-asmtp004.me.com>; Mon, 23 May 2016 19:32:20 +0000 (GMT) Received: from [172.17.133.77] (dip-cali.panasas.com [64.80.217.3]) by mr11p00im-asmtp004.me.com (Oracle Communications Messaging Server 7.0.5.36.0 64bit (built Sep 8 2015)) with ESMTPSA id <0O7N002DPA9UT630@mr11p00im-asmtp004.me.com>; Mon, 23 May 2016 19:32:19 +0000 (GMT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-05-23_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 clxscore=1011 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1510270003 definitions=main-1605230231 User-Agent: Microsoft-MacOutlook/f.16.0.160506 Date: Mon, 23 May 2016 12:32:31 -0700 Subject: Re: svn commit: r300421 - in head/sys: arm/allwinner arm/broadcom/bcm2835 arm/freescale/imx arm/mv dev/acpi_support dev/acpica dev/amdtemp dev/coretemp dev/iicbus powerpc/powermac From: Ravi Pokala Sender: "Pokala, Ravi" To: Warner Losh , Justin Hibbits Cc: src-committers , "svn-src-head@freebsd.org" , Luiz Otavio O Souza , "svn-src-all@freebsd.org" Message-id: Thread-topic: svn commit: r300421 - in head/sys: arm/allwinner arm/broadcom/bcm2835 arm/freescale/imx arm/mv dev/acpi_support dev/acpica dev/amdtemp dev/coretemp dev/iicbus powerpc/powermac References: <201605221358.u4MDwW8u097510@repo.freebsd.org> In-reply-to: MIME-version: 1.0 Content-type: text/plain; charset=UTF-8 Content-transfer-encoding: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mac.com; s=4d515a; t=1464031940; bh=T1jlCeEx0Mge6HqjjJgxHiXbNfXsM0Z1gGlkn6xzdHo=; h=Date:Subject:From:To:Message-id:MIME-version:Content-type; b=TYHkD7MRfvsI7VM52bb+TW8+4+ljuGnHFkFzr5UGBCt83gr3tRwsjcfYVxRWdVfse /ULkNLXotpehKmy+aAQ4r6BERejwb2uW1YVpWLT9pNqTQ7ArCMM24EWNyvsYUqDfnO HWJ0Vw1miEEEgYpifDvB410PoA1AvG+B0eZYlYzUyd/1UXT2eHiPJxnL6GqfXevEhM nXd3GEsatde623g7isVTa4YmPzocbLwPisF2fgJy4uKGBHqmO4/qtWMxo6KxU5T+SY PmAf6bBlm0uS7LtlqFH6Qt++vFl8A0IzzrL1Q15ASUhWn3H1zVQmpoZmv5Aj8yd9Va x6N3Sd7IC1xpg== X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 23 May 2016 19:32:26 -0000 -----Original Message----- From: on behalf of Warner Losh Date: 2016-05-23, Monday at 10:37 To: Justin Hibbits Cc: Ravi Pokala , src-committers , "svn-src-head@freebsd.org" , Luiz Otavio O Souza , "svn-src-all@freebsd.org" Subject: Re: svn commit: r300421 - in head/sys: arm/allwinner arm/broadcom/bcm2835 arm/freescale/imx arm/mv dev/acpi_support dev/acpica dev/amdtemp dev/coretemp dev/iicbus powerpc/powermac >On Sun, May 22, 2016 at 1:12 PM, Justin Hibbits wrote: >> >> On May 22, 2016 13:51, "Ravi Pokala" wrote: >>> >>> Out of morbid curiosity, why do these things report in deciKelvin anyway? >>> Are there sensors we support out there which report native Kelvin, or that >>> report sub-degree precision? >>> >>> Thanks, >>> >>> Ravi (rpokala@) >>> >> >> There are many i2c sensors which report in sub-degree centigrade. Though >> some of them are in 1/8 (or other power of 2) degree precision, not 1/10. > >ACPI reports in decikelvin, and it was the first thing we supported. Some 1 wire >devices support 1/16th a degree, and we support it in millikelvin since 1/16th >is 0.0625. So the precision needed is actually greater than what we're >reporting. >However, the accuracy of the measurement isn't +/- 0.001, it's closer >to +/1 0.063 >or so (well, that's a relative accuracy, absolute accuracy is closer >to +/- 1 degree). >We report the higher level of precision so that applications that use >the relative >temperature can use it to inform a control loop. We have no good way to report >relative precision for a measurement, or the absolute accuracy. > >Warner Good to know. Thanks guys. -Ravi