From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5808C1E0E14; Mon, 4 Aug 2025 00:42:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754268170; cv=none; b=HTnIxJ3ieUaoavVO4aEOrNwPgEN2dNSzn1erl4c8DFlhxd06uY7J9jBdP44Th4mAjv3x/jnnv1RqEPAQ+Q3wQx+pFJWuaajSDzStPlYpiey0ydzCiu0FvNAPzfffiG8QWSKfVjSp2jLOoaey/cRNC9DgjztVsnh4sCF0R7Cflig= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754268170; c=relaxed/simple; bh=hsfThi6DMIpLblPkuo8wfBtD+YC/NpXZOHHxBGMZ04s=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=k7vWNhVBHEixeD2lDtZcdIYI4huRn5cE09Qtg7So92dfqWIRXwCOWLlqwmEc8aWq157/82zlL3a/7o4vR24QtDiPFQSvzVG4uBHezdL5/Sg7tFr9ry2qomQSPLDReh5fGMezeD6DhFg5frCjf481SXeN+1Yh+z3LdAExRKdDxbk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IKfVjH/H; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IKfVjH/H" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0044AC4CEEB; Mon, 4 Aug 2025 00:42:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754268170; bh=hsfThi6DMIpLblPkuo8wfBtD+YC/NpXZOHHxBGMZ04s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IKfVjH/HSv/fdMwGoM0actImudPCfET18OEESirYqhpcbN+sbOOUvvXQsWTytMfev bM4nJP//T1nYZ4QF7SyuIJ5RksNei6EALR2CLcZQDaYn118ypPlS9z5BUfxPyEa0SK DuhfqpYu0ZaV/X7Q4cpzXlMTpiv9hswipjlbVMy+B9/MeMrKEJ7Ye79L759FcldfD2 3boPxTtG3nzXlmcVirEqdggJFDW1Nxq0EBpHAVHJxbXcSNLhkZqWK19euPDKchR57m Y2EyO8s5ur+pIlWfryynEKe2365w5TUIzAg6flt+D2m13I9cAYVImpNrq0NKJYErGL jZ708w+PrVGQQ== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Kuninori Morimoto , Mark Brown , Sasha Levin , lgirdwood@gmail.com, linux-sound@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 10/28] ASoC: soc-dapm: set bias_level if snd_soc_dapm_set_bias_level() was successed Date: Sun, 3 Aug 2025 20:42:09 -0400 Message-Id: <20250804004227.3630243-10-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250804004227.3630243-1-sashal@kernel.org> References: <20250804004227.3630243-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.4.296 Content-Transfer-Encoding: 8bit From: Kuninori Morimoto [ Upstream commit f40ecc2743652c0b0f19935f81baf57c601eb7f0 ] ASoC has 2 functions to set bias level. (A) snd_soc_dapm_force_bias_level() (B) snd_soc_dapm_set_bias_level() snd_soc_dapm_force_bias_level() (A) will set dapm->bias_level (a) if successed. (A) int snd_soc_dapm_force_bias_level(...) { ... if (ret == 0) (a) dapm->bias_level = level; ... } snd_soc_dapm_set_bias_level() (B) is also a function that sets bias_level. It will call snd_soc_dapm_force_bias_level() (A) inside, but doesn't set dapm->bias_level by itself. One note is that (A) might not be called. (B) static int snd_soc_dapm_set_bias_level(...) { ... ret = snd_soc_card_set_bias_level(...); ... if (dapm != &card->dapm) (A) ret = snd_soc_dapm_force_bias_level(...); ... ret = snd_soc_card_set_bias_level_post(...); ... } dapm->bias_level will be set if (A) was called, but might not be set if (B) was called, even though it calles set_bias_level() function. We should set dapm->bias_level if we calls snd_soc_dapm_set_bias_level() (B), too. Signed-off-by: Kuninori Morimoto Link: https://patch.msgid.link/87qzyn4g4h.wl-kuninori.morimoto.gx@renesas.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: Based on my analysis, here's my assessment: **Backport Status: YES** This commit should be backported to stable kernel trees for the following reasons: 1. **Bug Fix**: This is a clear bug fix that addresses an inconsistency in bias level management. The commit message clearly explains that `snd_soc_dapm_set_bias_level()` doesn't always update `dapm->bias_level`, particularly when dealing with card-level DAPM contexts where `snd_soc_dapm_force_bias_level()` is not called. 2. **Small and Contained**: The fix is minimal - it only adds 4 lines of code: ```c /* success */ if (ret == 0) snd_soc_dapm_init_bias_level(dapm, level); ``` This ensures that `dapm->bias_level` is always updated when the bias level change succeeds. 3. **Important Correctness Issue**: The inconsistency could lead to incorrect bias level tracking, which affects power management decisions in the ASoC subsystem. Code that checks `dapm->bias_level` (as shown in lines like `if (dapm->bias_level == SND_SOC_BIAS_ON)`) may make wrong decisions if the bias level isn't properly tracked. 4. **No Architectural Changes**: This is a straightforward fix that doesn't introduce new features or change the architecture. It simply ensures consistent behavior between the two bias level setting functions. 5. **Low Risk**: The change only affects the success path (when `ret == 0`) and uses an existing inline function `snd_soc_dapm_init_bias_level()` that simply sets `dapm->bias_level = level`. This is the same operation that `snd_soc_dapm_force_bias_level()` performs on success. 6. **Affects User-Facing Functionality**: Incorrect bias level tracking can lead to power management issues, potentially causing audio devices to not power up/down correctly, which directly impacts users. The commit fixes a real bug where the DAPM bias level state could become out of sync with the actual hardware state, particularly for card-level DAPM contexts. This is exactly the type of bug fix that stable kernels should include - it's small, targeted, fixes a real issue, and has minimal risk of introducing regressions. sound/soc/soc-dapm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c index 9f764d92469e..6142ce468c3b 100644 --- a/sound/soc/soc-dapm.c +++ b/sound/soc/soc-dapm.c @@ -741,6 +741,10 @@ static int snd_soc_dapm_set_bias_level(struct snd_soc_dapm_context *dapm, out: trace_snd_soc_bias_level_done(card, level); + /* success */ + if (ret == 0) + snd_soc_dapm_init_bias_level(dapm, level); + return ret; } -- 2.39.5