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 C726D30C60C; Sat, 25 Oct 2025 16:28:58 +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=1761409738; cv=none; b=O0sZxKGRNvWuWoWRtOHnarUgxUZKN1SKIy4T+0yILbV2a6osKf+3mgOoyi4UoQjnrEppYABoFVnMTNXS1dWVRPFYJ/q7cznJnPgeEDVA84bV0dvQ5LBEPD/z9eTSJqJD2F+n39ojyvMawuS3sq+IPFxk0HDWXtSbsjr2qyHI92E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761409738; c=relaxed/simple; bh=KuN0rYE5WO21s3BjY46USG2Aw+kKSQV2IfxwexUpeGc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=MYssNjvp46SvQpshp/T98NGe7PnIOfOZt3NW73canOk4G7J3iltxpHLffSwq6yp68U7LEKBFIkZ2kIvcDeekNNP6QhsdmYjLpUuvVtn6FrnOP1HRzSLaw0p/yPyYhhJVhl/aL+88Br6l7Akh9co72r0qcol1sKqDtVx1BKrrEHk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=m1Gw/umw; 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="m1Gw/umw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E6F1C4CEF5; Sat, 25 Oct 2025 16:28:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761409738; bh=KuN0rYE5WO21s3BjY46USG2Aw+kKSQV2IfxwexUpeGc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m1Gw/umwIA1AqNSS8IRN9eAucPutiopAe1sDcY11HeLxsxIbSKE9vFF1vgevtrKET qYrT0GSD1mbdzidocEbCHGBpZpUpAvi8dVCkQJMsY2s36SFfR6CgRSahg/IP5dOs8J XovMZfeoiMA2+w1xmYahJGOUQ8pV9xp5hUeKVzkT5ivzCPHbJNze4p2qaOKMFpkDEE xk/OXXdLWo9ZSIYf3OK238UuOIf0eSgEoKtlkiIP2r0t0e8DSriEoawepTD6sD0ksa Ho+DIjlPbrefmTsGxx43nanr7ru20Eji4SuWnYjOA/ITQBJd3Kd4OJYtnwM+zj3Cdr KoVbTS2lqbudA== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Peter Wang , "Martin K. Petersen" , Sasha Levin , matthias.bgg@gmail.com, angelogioacchino.delregno@collabora.com, linux-scsi@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 6.17-6.12] scsi: ufs: host: mediatek: Correct system PM flow Date: Sat, 25 Oct 2025 12:01:15 -0400 Message-ID: <20251025160905.3857885-444-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251025160905.3857885-1-sashal@kernel.org> References: <20251025160905.3857885-1-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 6.17.5 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Peter Wang [ Upstream commit 77b96ef70b6ba46e3473e5e3a66095c4bc0e93a4 ] Refine the system power management (PM) flow by skipping low power mode (LPM) and MTCMOS settings if runtime PM is already applied. Prevent redundant operations to ensure a more efficient PM process. Signed-off-by: Peter Wang Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: YES - Fixes a real PM logic bug. Without this change, the Mediatek UFS driver forces VSx/regulators out of LPM and re-enables MTCMOS during system resume even if the device is runtime-suspended, which violates the runtime PM state and can wake hardware spuriously (extra power draw or mis-ordered bring-up). The core UFS system PM paths already skip work if the device is runtime-suspended; the Mediatek vendor code must mirror that behavior. - Aligns vendor flow with core UFS PM semantics. Core checks `pm_runtime_suspended(hba->dev)` and bails from system PM work in both suspend and resume (drivers/ufs/core/ufshcd.c:10284, drivers/ufs/core/ufshcd.c:10311). This patch adds the same guards to the Mediatek hooks so vendor-specific toggles are not performed on a runtime-suspended device. - Corrects ordering on resume. It powers the MTCMOS domain before changing device regulator LPM, matching the already-correct runtime PM path and avoiding SMC/PM operations while the domain is off. Key code changes and impact: - Add guard in system suspend to skip vendor LPM/MTCMOS when runtime- suspended: - `if (pm_runtime_suspended(hba->dev)) goto out;` drivers/ufs/host/ufs-mediatek.c:2380 - Prevents redundant `ufs_mtk_dev_vreg_set_lpm(hba, true)` and `ufs_mtk_mtcmos_ctrl(false, ...)` calls when runtime PM already put the device in low power (drivers/ufs/host/ufs-mediatek.c:2383, drivers/ufs/host/ufs-mediatek.c:2386). - Add guard in system resume to preserve runtime-suspended state: - `if (pm_runtime_suspended(hba->dev)) goto out;` drivers/ufs/host/ufs-mediatek.c:2398 - Avoids powering on MTCMOS and clearing LPM when device should remain runtime-suspended. - Fix resume sequencing to match runtime resume: - Enable MTCMOS before clearing LPM: `ufs_mtk_mtcmos_ctrl(true, ...)` then `ufs_mtk_dev_vreg_set_lpm(hba, false)` (drivers/ufs/host/ufs- mediatek.c:2401, drivers/ufs/host/ufs-mediatek.c:2404). - Mirrors the runtime path order (drivers/ufs/host/ufs- mediatek.c:2442, drivers/ufs/host/ufs-mediatek.c:2448). - Always invoke core system resume for tracing/consistency (drivers/ufs/host/ufs-mediatek.c:2406). Why it fits stable: - Small, contained fix limited to Mediatek UFS host. - No API changes; just conditionalizing existing operations and correcting order. - Prevents incorrect power-state transitions and redundant SMC/PM ops; low regression risk. - Aligns with core driver’s established PM behavior, reducing divergence and surprises. Given these factors, this is an important behavioral fix with minimal risk and should be backported. drivers/ufs/host/ufs-mediatek.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/drivers/ufs/host/ufs-mediatek.c b/drivers/ufs/host/ufs-mediatek.c index 6bdbbee1f0708..91081d2aabe44 100644 --- a/drivers/ufs/host/ufs-mediatek.c +++ b/drivers/ufs/host/ufs-mediatek.c @@ -2264,27 +2264,38 @@ static int ufs_mtk_system_suspend(struct device *dev) ret = ufshcd_system_suspend(dev); if (ret) - return ret; + goto out; + + if (pm_runtime_suspended(hba->dev)) + goto out; ufs_mtk_dev_vreg_set_lpm(hba, true); if (ufs_mtk_is_rtff_mtcmos(hba)) ufs_mtk_mtcmos_ctrl(false, res); - return 0; +out: + return ret; } static int ufs_mtk_system_resume(struct device *dev) { + int ret = 0; struct ufs_hba *hba = dev_get_drvdata(dev); struct arm_smccc_res res; + if (pm_runtime_suspended(hba->dev)) + goto out; + ufs_mtk_dev_vreg_set_lpm(hba, false); if (ufs_mtk_is_rtff_mtcmos(hba)) ufs_mtk_mtcmos_ctrl(true, res); - return ufshcd_system_resume(dev); +out: + ret = ufshcd_system_resume(dev); + + return ret; } #endif -- 2.51.0