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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 99992C54EE9 for ; Mon, 19 Sep 2022 14:19:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229456AbiISOTn (ORCPT ); Mon, 19 Sep 2022 10:19:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42860 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229645AbiISOTm (ORCPT ); Mon, 19 Sep 2022 10:19:42 -0400 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0DD632BD8; Mon, 19 Sep 2022 07:19:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1663597181; x=1695133181; h=date:from:to:cc:subject:in-reply-to:message-id: references:mime-version; bh=+1jJkKo3oDnZITK1ZKuYSzyR0/mdILKfueu7BEmDvLI=; b=bLTCKVOqxIa7bgTn+erQiB2zVwQq0Q/5liC7Z7YFJAAvw+QdVz2RzxPB /TnOlCaWDEJzZXiby8+N0lR2SLR6wNcYsNZk60YDXoWNyQSWXv71WE4yR Db8K+LUiENhMcOAmm6tZrQKVUkNl7TznUdgfCorhiBCdGbUd5oqPgLO7A 9I2JTkK4/wpLaeZF5woxgLSt2JPU62WbnNYYHYeCW+rXDW0RDxT/N7wsq Io4vbISQevzwxK5H6KZ0SKJSiyYgVhpEbtCa8wU4VAAFixU0pKkdPnI/p CMRsJxwOzHs3Lp+jc2U2xO4hcWpCGtmpW42WvgA0UB2eAbGYQwq23WjIS w==; X-IronPort-AV: E=McAfee;i="6500,9779,10475"; a="300230010" X-IronPort-AV: E=Sophos;i="5.93,328,1654585200"; d="scan'208";a="300230010" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Sep 2022 07:19:40 -0700 X-IronPort-AV: E=Sophos;i="5.93,328,1654585200"; d="scan'208";a="707582398" Received: from iswiersz-mobl1.ger.corp.intel.com ([10.252.33.172]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Sep 2022 07:19:37 -0700 Date: Mon, 19 Sep 2022 17:19:35 +0300 (EEST) From: =?ISO-8859-15?Q?Ilpo_J=E4rvinen?= To: Andy Shevchenko cc: Lennert Buytenhek , Greg Kroah-Hartman , Jiri Slaby , linux-serial , LKML Subject: Re: I/O page faults from 8250_mid PCIe UART after TIOCVHANGUP In-Reply-To: Message-ID: References: <7fd034a9-c1e1-2dca-693b-129c9d2649@linux.intel.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="8323329-1542528522-1663597179=:1603" Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323329-1542528522-1663597179=:1603 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT On Mon, 19 Sep 2022, Andy Shevchenko wrote: > On Fri, Sep 16, 2022 at 02:47:08PM +0300, Lennert Buytenhek wrote: > > On Thu, Sep 15, 2022 at 07:27:45PM +0300, Ilpo Järvinen wrote: > > ... > > > Thanks for the fix! > > > > > [...] I'm far from sure if it's the > > > best fix though as I don't fully understand what causes the faults during > > > the THRE tests because the port->irq is disabled by the THRE test block. > > > > If the IRQ hasn't been set up yet, the UART will have zeroes in its MSI > > address/data registers. Disabling the IRQ at the interrupt controller > > won't stop the UART from performing a DMA write to the address programmed > > in its MSI address register (zero) when it wants to signal an interrupt. > > > > (These UARTs (in Ice Lake-D) implement PCI 2.1 style MSI without masking > > capability, so there is no way to mask the interrupt at the source PCI > > function level, except disabling the MSI capability entirely, but that > > would cause it to fall back to INTx# assertion, and the PCI specification > > prohibits disabling the MSI capability as a way to mask a function's > > interrupt service request.) > > This sounds to me like a good part to be injected into commit message of > the proposed fix. I added my own wording already but I could adds of Lennert's far superior descriptions verbatim if he is OK with that? -- i. --8323329-1542528522-1663597179=:1603--