From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.10]) (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 C815A3EF67B; Mon, 29 Jun 2026 14:56:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782745000; cv=none; b=IWb8AF4uP/9x3uhPv2ndCoJjkE8vVNEhasmTt9TLFiwXLutWEBQ4LgwQ8xz5rDxLYcQksnI+yDDz1V2Sk1VGoD3GDl2mnv3KaC0tc/hxf3jLdL7G/xjpFJ4uBumUC7KkEBGoQ5zvBCiXFVgJrg++OXNU3plRJAcp/GqLKu+iFco= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782745000; c=relaxed/simple; bh=DhvShMfkDmzhr54JwFXiy08k/7PFXGfy8mHmxHdzRQg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=B6HfqrH3RzCLd5Iy0BYwTpEZAXONK6bSmJ7b6Kmwbgq7ezc6MPzKQa/RBarBLS5UxYysSIKZWU6J5rpLOV24lTOUGjhPXTssymBG0RWfMegh2E860EpyB8sm4HUzHaUImCMAzliApZQ2fyupgtpkVh4Ivjt0rUfWJmKMf6ClbTs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=OF4slGCo; arc=none smtp.client-ip=198.175.65.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="OF4slGCo" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1782744999; x=1814280999; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=DhvShMfkDmzhr54JwFXiy08k/7PFXGfy8mHmxHdzRQg=; b=OF4slGCokVill0POLRYYpGPArkNezv5KPhIRecLMTvBb0Y+XX3dOryrY 6b5yH+R+uTQ06K7zKp+HZw9xivH2/1EZjtUJ5nwaDzVtQpEt9KbqeB8ay OCkc2r6PrKt9rXywSh1QY5s++ky5dLkHiHhiWNx7m3Pajpt9yAkLPN00+ 9f0Ta7dkuq/AWZyAC2k0pdy6jkGtSE87haq7qFrsJDzsW2/04CyWRj73L qALKfgvYmgGp99n2W/ylixeE1MOxbF1BjAhIUAhjTD/A6ZdFjzJbUgCqH izS8M+GoRgZilujBLKSIg7nnd4V27flYj2YX59d8ONnr1PYxeDGn/7WpK g==; X-CSE-ConnectionGUID: FHboFNTcSEC/zrRLmNZX+w== X-CSE-MsgGUID: ZaEnx2a2RzyoA3q+cZqPvg== X-IronPort-AV: E=McAfee;i="6800,10657,11832"; a="100870406" X-IronPort-AV: E=Sophos;i="6.24,232,1774335600"; d="scan'208";a="100870406" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by orvoesa102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jun 2026 07:56:39 -0700 X-CSE-ConnectionGUID: PUPo7NY0SxOnNRseC1Nuag== X-CSE-MsgGUID: swAMMlsoSvGDyJr6IjR/bQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.24,232,1774335600"; d="scan'208";a="275208649" Received: from kniemiec-mobl1.ger.corp.intel.com (HELO localhost) ([10.245.244.207]) by fmviesa002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jun 2026 07:56:36 -0700 Date: Mon, 29 Jun 2026 17:56:33 +0300 From: Andy Shevchenko To: Yicong Yang Cc: ilpo.jarvinen@linux.intel.com, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org, jirislaby@kernel.org, geshijian@picoheart.com, yangyang.8776@picoheart.com, yanligen@picoheart.com Subject: Re: [PATCH] serial: 8250_dw: Prefer SRBR in bogus RX timeout workaround if available Message-ID: References: <20260629075510.32854-1-yang.yicong@picoheart.com> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260629075510.32854-1-yang.yicong@picoheart.com> Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo On Mon, Jun 29, 2026 at 03:55:10PM +0800, Yicong Yang wrote: > The DW uart could get into the cases where a bogus RX timeout > interrupt is asserted but no available data. This could be > workaround by doing a bogus read. > > Currently the driver's using the standard RBR (receive buffer > register) for this bogus read. However the reading of RBR > in this case is allowed to raise a hardware error if vendor > choose to implement in this way (our platform). It's also > allowed to do the bogus read using SRBR (shadow RBR) for > workaround which won't raise the hardware error. So change > to use the SRBR to workaround the issue if it's available. ... > /* Offsets for the DesignWare specific registers */ > +#define DW_UART_SRBR_0 0x0c /* Shadow Receive Buffer Register */ Is this a name per DesignWare databook for UART? I mean that _0 part. -- With Best Regards, Andy Shevchenko