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 B2E7E1CAA4; Tue, 14 May 2024 11:59:19 +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=1715687959; cv=none; b=uiyZp7iw4fxU8A6P10LX86/s0H4yBPiA/bLs48cduazX/9ziSYQ/ckojE/uebNOAysR3mOiH3Nn6EU71FmgVV6MLOUSjNJ4CNvjrrKH61w13BPc2UcPAXw22yf/EJQz4scn70KvOO1lItTfGmy1Yzgaoz288U3M/jZ+2uGuosV4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715687959; c=relaxed/simple; bh=qcCiN2uVc2X4EwiWZsOpi6iMpWms9a4Atew8nEO12XE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nRnM95vCBFrGHVr0aVVS0cjKWqzmOlfHXKllAk0ZjUVzSbJQdb+Nm8c1QC1MDefYM493jKvRn8tNsgZdTemPdf3LyHWPsZSM853vB+RDJOD/EIrpRHEFwFJRISG9JOTiXIW1FjZ0qPRK5GVPA43F0Poe5urlz69d2J9sIizyzTw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=nztuC81I; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="nztuC81I" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F1743C2BD10; Tue, 14 May 2024 11:59:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1715687959; bh=qcCiN2uVc2X4EwiWZsOpi6iMpWms9a4Atew8nEO12XE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nztuC81Iolk7R7d4eHKpOeNDyCHjr2sR+7M6+++hG8kREwwIlDCRnPYcTC5Ehlv8q 24Xq+nD793QQ7qbxLJ4mr/LTgJJWAoEUwQckp3XKor1/fBnQxak7IbKKAaQIS57OUK Uy/eCIVw4TrCv0S3gPe9B+Q5Qffmy8OH3cXxKYWo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Lakshmi Yadlapati , Eddie James , Guenter Roeck Subject: [PATCH 5.15 164/168] hwmon: (pmbus/ucd9000) Increase delay from 250 to 500us Date: Tue, 14 May 2024 12:21:02 +0200 Message-ID: <20240514101012.948069311@linuxfoundation.org> X-Mailer: git-send-email 2.45.0 In-Reply-To: <20240514101006.678521560@linuxfoundation.org> References: <20240514101006.678521560@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lakshmi Yadlapati commit 26e8383b116d0dbe74e28f86646563ab46d66d83 upstream. Following the failure observed with a delay of 250us, experiments were conducted with various delays. It was found that a delay of 350us effectively mitigated the issue. To provide a more optimal solution while still allowing a margin for stability, the delay is being adjusted to 500us. Signed-off-by: Lakshmi Yadlapati Link: https://lore.kernel.org/r/20240507194603.1305750-1-lakshmiy@us.ibm.com Fixes: 8d655e6523764 ("hwmon: (ucd90320) Add minimum delay between bus accesses") Reviewed-by: Eddie James Cc: stable@vger.kernel.org Signed-off-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman --- drivers/hwmon/pmbus/ucd9000.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/drivers/hwmon/pmbus/ucd9000.c +++ b/drivers/hwmon/pmbus/ucd9000.c @@ -80,11 +80,11 @@ struct ucd9000_debugfs_entry { * It has been observed that the UCD90320 randomly fails register access when * doing another access right on the back of a register write. To mitigate this * make sure that there is a minimum delay between a write access and the - * following access. The 250us is based on experimental data. At a delay of - * 200us the issue seems to go away. Add a bit of extra margin to allow for + * following access. The 500 is based on experimental data. At a delay of + * 350us the issue seems to go away. Add a bit of extra margin to allow for * system to system differences. */ -#define UCD90320_WAIT_DELAY_US 250 +#define UCD90320_WAIT_DELAY_US 500 static inline void ucd90320_wait(const struct ucd9000_data *data) {