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X-CSE-ConnectionGUID: +GjJMY74S2qXd43W227FIQ== X-CSE-MsgGUID: l3QZRgpnT3iAsgkBqIVTUg== X-IronPort-AV: E=McAfee;i="6800,10657,11901"; a="89271664" X-IronPort-AV: E=Sophos;i="6.27,95,1787036400"; d="scan'208";a="89271664" Received: from fmviesa006.fm.intel.com ([10.60.135.146]) by orvoesa112.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Sep 2026 08:39:52 -0700 X-CSE-ConnectionGUID: pwE6b1uxSfylZKhdjLrIUQ== X-CSE-MsgGUID: o7PHWUCcTUm2vIiLKEoEig== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,95,1787036400"; d="scan'208";a="267395256" Received: from ncintean-mobl1.ger.corp.intel.com (HELO localhost) ([10.245.245.177]) by fmviesa006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Sep 2026 08:39:46 -0700 Date: Thu, 10 Sep 2026 18:39:43 +0300 From: Andy Shevchenko To: zl020895 Cc: Ilpo =?iso-8859-1?Q?J=E4rvinen?= , longzhao@ambarella.com, Arnd Bergmann , Krzysztof Kozlowski , Alexandre Belloni , soc@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Rob Herring , Krzysztof Kozlowski , Conor Dooley , Michael Turquette , Stephen Boyd , Linus Walleij , Bartosz Golaszewski , Greg Kroah-Hartman , Jiri Slaby , Catalin Marinas , Will Deacon , Lee Jones , mfd@lists.linux.dev, devicetree@vger.kernel.org, linux-clk@vger.kernel.org, linux-gpio@vger.kernel.org, linux-serial , LKML Subject: Re: Re: Re: [PATCH v6 11/13] serial: 8250_dw: add Ambarella CV75 quirks Message-ID: References: <20260904-cv75-v5-v6-0-e918514cb3b1@ambarella.com> <20260904-cv75-v5-v6-11-e918514cb3b1@ambarella.com> <122573f8.8232.1a08a9765fc.Coremail.zl020895@163.com> <55b27872.8ed9.1a08ab55a52.Coremail.zl020895@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <55b27872.8ed9.1a08ab55a52.Coremail.zl020895@163.com> Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260910_083953_346477_0529DBDE X-CRM114-Status: GOOD ( 20.55 ) 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 Thu, Sep 10, 2026 at 05:45:36PM +0800, zl020895 wrote: > Hi Ilpo, Andy, > > I'll go with the simple comment: > /* > * Ambarella keeps variant IER bits (e.g. ETOI) set for correct RX > * timeout behaviour. > */ > up->ier |= d->pdata->ier_mask; Works for me. > At 2026-09-10 17:33:38, "Ilpo Järvinen" wrote: > >On Thu, 10 Sep 2026, Andy Shevchenko wrote: > >> On Thu, Sep 10, 2026 at 05:12:52PM +0800, zl020895 wrote: > >> > >> > > Wondering if we should undo this in the port's .shutdown() callback. > >> > I saw the shutdown path already covers it: dw8250_shutdown() calls > >> > serial8250_do_shutdown(), which does > >> > up->ier = 0; > >> > serial_port_out(port, UART_IER, 0); > >> > so both the IER shadow and hardware IER are cleared, including ETOI. > >> > >> Depending on the answer to Ilpo the enabling may need an updated comment > >> summarising the above. > > > >I'd prefer removing the entire "Force them ..." sentence, it feels really > >basic detail about how ->ier works. I believe that would resolve your > >concern if relates to what shutdown does for the flag (clears it while > >the comment as is says nothing is supposed to clear it). > > > >> > At 2026-09-10 16:33:14, "Andy Shevchenko" wrote: > >> > >On Fri, Sep 04, 2026 at 02:38:18PM +0800, Long Zhao via B4 Relay wrote: ... > >> > >> + /* > >> > >> + * Ambarella keeps variant IER bits (e.g. ETOI) set for correct RX > >> > >> + * timeout behaviour. Force them into the 8250 IER shadow so later > >> > >> + * generic IER updates do not clear them. > >> > >> + */ > >> > > > >> > >Wondering if we should undo this in the port's .shutdown() callback. -- With Best Regards, Andy Shevchenko