From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5E9C6CA5FE2 for ; Mon, 5 Oct 2026 06:55:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=0NuiB/b5/WbYYEyiXEGqACpXXyEMDlEux42pPiuE6qU=; b=tGV/DxbiVMmLAhNiBy5LkYW2ON 4Cjxa4Y/M09Khk0ptVgnKhSp2OcERqHw2Hg8qYiByoascUEGCP0n5lEZ/LgtV4NGEWlaZdoqoIi1k sJDvQnO0FAPlhQ748etwEDjmA3pX99IzGU+9nvIOKNZQcBL18foc3Qty0VsST3smfugPLXRFdPXA0 iGAKUerxIdVcEmJFnJJGM3WU06vBjOYg4wc/V1SNTf2UvJe4/X6ir0g1KS4XLogGpYYHvrfken+QT yy7r4QyCOKS0aR7za0a3cZiZYLx/5SOq0cv1WoWaBO6rzslIJhX+86ynPcrYruKOzQnMln4ZreY/3 a+MolIOg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xDcbU-0000000Fkop-3qwS; Mon, 05 Oct 2026 06:55:16 +0000 Received: from mx.socionext.com ([202.248.49.38]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xDcbR-0000000FkoN-47sc for linux-arm-kernel@lists.infradead.org; Mon, 05 Oct 2026 06:55:15 +0000 Received: from unknown (HELO iyokan3-ex.css.socionext.com) ([172.31.9.54]) by mx.socionext.com with ESMTP; 05 Oct 2026 15:55:10 +0900 Received: from mail.mfilter.local (mail-arc01.css.socionext.com [10.213.46.36]) by iyokan3-ex.css.socionext.com (Postfix) with ESMTP id BB12D2091574; Mon, 5 Oct 2026 15:55:10 +0900 (JST) Received: from iyokan3.css.socionext.com ([172.31.9.53]) by m-FILTER with ESMTP; Mon, 5 Oct 2026 15:55:10 +0900 Received: from [10.213.138.49] (unknown [10.213.138.49]) by iyokan3.css.socionext.com (Postfix) with ESMTP id 06E4810D843; Mon, 5 Oct 2026 15:55:10 +0900 (JST) Message-ID: <632a5ff5-89e3-437d-b89e-dbcef35fbd49@socionext.com> Date: Mon, 5 Oct 2026 15:55:10 +0900 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] serial: 8250_uniphier: Use devm_clk_get_enabled() To: Andy Shevchenko Cc: Malathi A , Greg Kroah-Hartman , Jiri Slaby , Masami Hiramatsu , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <20260917040511.103232-1-malathi.a2000@gmail.com> <97e4ab26-b147-4cf4-97f9-307903f14e61@socionext.com> <3ea1f574-ddb5-46a6-9bc1-7a8ea84c54bd@socionext.com> Content-Language: en-US From: Kunihiko Hayashi In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261004_235514_146434_8B700A61 X-CRM114-Status: GOOD ( 23.30 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2026/09/28 18:05, Andy Shevchenko wrote: > On Mon, Sep 28, 2026 at 03:51:09PM +0900, Kunihiko Hayashi wrote: >> On 2026/09/25 22:37, Andy Shevchenko wrote: >>> On Fri, Sep 25, 2026 at 08:32:20PM +0900, Kunihiko Hayashi wrote: >>>> On 2026/09/24 23:09, Andy Shevchenko wrote: >>>>> On Thu, Sep 24, 2026 at 06:07:37PM +0900, Kunihiko Hayashi wrote: >>>>>> On 2026/09/17 13:05, Malathi A wrote: > > ... > >>> So, in such a case how do you see the scenario when system is resumed >>> (Right? >>> Otherwise we can't do anything, like detaching driver from the device.) >>> and >>> clock is disabled? >> >> Ah, I understand your point. I was assuming that the driver could later >> be detached after uniphier_uart_resume() failed, leaving the clock disabled. > > I'm not sure, I don't know if I was right. Can you confirm that this scenario > is not possible? So, it might look like CPU is resumed, some of the devices > were resumed, but this particular UART failed to resume, and now we want to > detach it. If this case is possible, I believe tons of the device drivers as > of today may be affected by the same issue (it doesn't mean that the issue > is impossible to happen, one needs to investigate deeper) Sorry for the delayed reply. Unfortunately, I can't confirm whether this scenario is impossible. I don't currently have an environment where I can reproduce this system suspend/resume case either. I agree that if a device can later be detached after its system resume callback has failed, this may affect other drivers using the same pattern as well, and determining that seems to require a deeper look into the PM core behavior. >> If that sequence cannot happen after a failed system resume, then my concern >> doesn't apply. > > As pointed out I'm not sure. Last time I experimented with failed resume > long time ago. So I don't have a definitive answer here either, and can only point out this as a potential issue for now. Thank you, --- Best Regards Kunihiko Hayashi