From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lf1-f45.google.com (mail-lf1-f45.google.com [209.85.167.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EAAB41804E for ; Mon, 22 Apr 2024 05:52:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713765133; cv=none; b=ZMKboLaY8mgGbVrKKQgeXfgyLQx2WLTcdLPAJSxwNB0WFs76DzhIAO/jt8OffAjFY9n+zaSjfbdRZTK8N9pm6S3HNlmOq6tl03UUIM5U/zp6G+QfV65btKJGSrF1PN5kF+nWt4T9FHFANlgsBY4FUpm7DeRn0kucdUg7LVhNsnI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713765133; c=relaxed/simple; bh=TxQUciVEnGFCKIhiOQPPvv8IseNZKshmRL1p3LyPowc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=lrT8a8tDS04FkAKnZxIIZ+ZJWZLgk2VQ9VSgvEEj17osNQ19rwO+ga2QoJTvlX5Tt/KYW1bqyEGSSLZdnxdJwlbgi7X0jC3vYJCDG4dbH52BITj0QYSNwsGgvdvX1pW4yjj6GW12jy4cNCtorGvUbKxdV2Yd/7S4VaJCEqzIuYE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=lxpiCznx; arc=none smtp.client-ip=209.85.167.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="lxpiCznx" Received: by mail-lf1-f45.google.com with SMTP id 2adb3069b0e04-516d2600569so4986689e87.0 for ; Sun, 21 Apr 2024 22:52:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1713765130; x=1714369930; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=yS29vThG06rh1rP64dQkWUwKf62kA7HWXn+snVcWWCg=; b=lxpiCznx3pW2QttM8hYUhdpJggCYlKUV6IzDXKYl1i3ur2I1QdmiI1IOTv4SiXNUYD FM0GbMci6QGDWq3BIGOKRsTKiGo6nmDjQ3njNPcJlqlA7/7ZkCfVj9U84A0ficVPqwmG 686zm2b2uciH9BW8CdFc2hTnFNe4HWEbW8toY33+3+twLOSytu9bmdixj/jcbIOU+pYd oOhZTnjkmEOgVYol6UIkM4LBMH3FHnQ3NeaNuLvkE3nsuNMHI+kgeM/EUFb+tOluS8/5 FWwVUSwIMRbyzupWagjjPXzogieZLUBcx23M3RKEQAOKm76KpSU33C/HvRpDurKVqb9a sEEg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1713765130; x=1714369930; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=yS29vThG06rh1rP64dQkWUwKf62kA7HWXn+snVcWWCg=; b=ipslMjzAN+1dCDlolaBCYviOOIdYwiXkXkcwZ2aCsDEhS8N0zuORmodh0hWVIbN4YB ws5eMQS50MxCdbcfOZQQ5yR8vIOvZonLtT6oopFEkE6VVREm6qmfaTAPBCmKM+wJf9d1 WryHdI6PaLGKxL7Zgzxp6rDfSsDl2PA6NvU1H17dlzQfr6MsH7nQWlCemxTnAK420pmC OiyGu+QA60XOdwW8H6c2zIPvfgT1YLWDibql9RfD4u/GZSxD8aO4qIgV23QOGNLQimOq CsDbSHTfvnEJKi2BMX1TsvqwXC75H/j7cz3BS37ALcaWf5x6BSB9JgFOlJ8XrQ3sppVH aqhA== X-Gm-Message-State: AOJu0Yxb5tOc2xvIy+Ogo0bpBCVzzx5gVq3pJvLsq81SzczesdXqC2qa iydRgwiTqUnpThVEfaL9YZrATaGQPMDUZA1JkQAxCcDLL763mhgu X-Google-Smtp-Source: AGHT+IFzSHLAky22cDQ62MASgUpJjQu3qXPO3w2BM3nxE3HKK1ZjTY6NG3mZ1AvvxrPLHjXUEErX2g== X-Received: by 2002:a05:6512:33c3:b0:516:d55b:3123 with SMTP id d3-20020a05651233c300b00516d55b3123mr7877171lfg.20.1713765129803; Sun, 21 Apr 2024 22:52:09 -0700 (PDT) Received: from ?IPV6:2001:14ba:7426:df00::2? (drtxq0yyyyyyyyyyyyyby-3.rev.dnainternet.fi. [2001:14ba:7426:df00::2]) by smtp.gmail.com with ESMTPSA id n23-20020a05651203f700b00518a3f2e3dcsm1641274lfq.57.2024.04.21.22.52.09 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 21 Apr 2024 22:52:09 -0700 (PDT) Message-ID: <2cc46844-75af-4da3-aa56-3f69a5ed3dfb@gmail.com> Date: Mon, 22 Apr 2024 08:52:04 +0300 Precedence: bulk X-Mailing-List: linux-hwmon@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Regression in lm90 driver regarding GMT g781 To: Guenter Roeck , Aleksander Mazur Cc: linux-hwmon@vger.kernel.org, Mark Brown References: <20240420183427.0d3fda27@mocarz> <20240420223824.624e725b@mocarz> <04831e1c-9957-4750-b438-9d5395b8fa45@roeck-us.net> Content-Language: en-US, en-GB From: Matti Vaittinen In-Reply-To: <04831e1c-9957-4750-b438-9d5395b8fa45@roeck-us.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 4/21/24 00:20, Guenter Roeck wrote: > On Sat, Apr 20, 2024 at 10:38:24PM +0200, Aleksander Mazur wrote: >> Dnia 2024-04-20, o godz. 11:14:06 >> Guenter Roeck napisał(a): >> >>> On Sat, Apr 20, 2024 at 06:34:27PM +0200, Aleksander Mazur wrote: >>>> Hello, >>>> >>>> I have a Wyse C00X thin client which is apparently equipped with GMT g781. >>>> It is (or used to be) supported by lm90 driver. (I have a log from 2020 >>>> where it was simply working fine; it was kernel version 5.6.0 then.) >>>> Now, with 6.8.7, I get following error: >>>> >>>>> lm90 0-004c: Failed to enable regulator: -ENODEV >>>> >>>> However, when I just turned this message into a warning and let the driver >>>> continue, it seems to work fine, providing temp1 and temp2 as previously. >>>> >>>> Do you have an idea what could cause such a regression, and if this change >>>> (I mean: simply not returning error from devm_regulator_get_enable) is safe? >>>> >>> >>> Do you have CONFIG_REGULATOR enabled in your system ? >>> >>> Guenter >> >> No, it's disabled (and it was disabled in 5.6.0 as well). >> > I thought so. It works in v6.1 and earlier kernels because > devm_regulator_get() returns NULL if CONFIG_REGULATOR=n. > The driver used that function prior to commit ad804a4d82fc > ("hwmon: (lm90) simplify using devm_regulator_get_enable()"). > >> Shouldn't devm_regulator_get_enable*() stubs return success instead of -ENODEV? >> > > One might think so, but apparently the author thought otherwise. Apparently the author has not known what he is doing :) I have a faint memory that I chose to return an error because some of the other stubs did that. Looking at the header, it seems the variants of *_regulator_get_optional() and *_regulator_get_exclusive() return an error, which may be where I picked the return value. Now, thinking of the use-cases and the comment in the stub of the regulator_get() - I think we should just return success from the stub. I'll send a patch and let's see what Mark says. Sorry for the hassle. -- Matti > It looks > like the function can not be used for drivers which have to work with > CONFIG_REGULATOR=n. The only option I can see is to revert commit > ad804a4d82fc because that commit doesn't just simplify the code but also > make regulator support mandatory. Matti, do you have a better idea ? > Other hwmon drivers are affected as well, so we'll need a common solution. > > Aleksander, for your use case, you can just drop the offending code > until the fix (or revert) makes it upstream. Sorry for the trouble. > > Thanks, > Guenter -- Matti Vaittinen Linux kernel developer at ROHM Semiconductors Oulu Finland ~~ When things go utterly wrong vim users can always type :help! ~~