From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx.socionext.com (mx.socionext.com [202.248.49.38]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 3D779309EF9; Mon, 5 Oct 2026 06:55:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=202.248.49.38 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791183320; cv=none; b=DAPTaKyW+J4w2KIAIh6fsc/rGfs05cNcrhfdODDKQDvfDT1Y6wUZWDB3n+M7hfracpGYXqEyCAtL/WkgkSfpev8KWvMIV+q9p0PC+hzAcLHxput1XsbpHHWjYku1a+QpS6MFxomX89iTvbReeKU0SRaVoNMxDUX1ggDsNCLApO0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791183320; c=relaxed/simple; bh=2+5aCRKqLwTz8H515JmkRlWIvUqb7saKt0q45ibTiIY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=SZanv1RHYxgw1BUq+CS1PrL/5jF1UuJijWEtbHsUG4FrOtIZQSTNREXVZXOYhDK7FRoR8pnPGK/YM792Um8lgnysJx/5j2jdfKSi6Sxz7k5kVhliLA5sDgDeAFVjXk5+5YKhig/+jRYIUBX6B7mEFN+x0VhZlCVsul95ggF7n44= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=socionext.com; spf=pass smtp.mailfrom=socionext.com; arc=none smtp.client-ip=202.248.49.38 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=socionext.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=socionext.com 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 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 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