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 X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35546C2B9F4 for ; Tue, 22 Jun 2021 06:17:26 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id E856960FDC for ; Tue, 22 Jun 2021 06:17:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E856960FDC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=siemens.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:Cc:To:Subject:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=evy4K4j57s6GraaEQkuWkCpr3Syxs5U9750DdN2eDTQ=; b=C4pXc4/aNZYR5EDx3ZBBZaUUdb N+CT8xNavGdCGsNclKKz++C+S7zBPh6LibJyFsE5k04Ne7c1ELoMlHD2q+X+7G6wzVoAoJRHKIo33 nlR4yuE5iIwwktfj5aULbE8gRfH+iUGyoKxYieqIC5pf7+eENVtAzRdVgpWU9A86Ajk8wltrk0wvW kRuo4gRCdW6Nx1X0/X2mGCdmEVbCtBZ+6k2XyFlx/hvBS2kKPnacmLOWzTRSxEyKNkLCqNv9B49a7 5KeXBAwhMkA1p9N4zyJPe7ecUIsIsZ2B7UqizK9nt/jS6gQv5EvYL0hc015S8Or8MFqbJ7ZNnLLi9 XlkTUiuA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lvZhH-005nEk-HL; Tue, 22 Jun 2021 06:15:43 +0000 Received: from gecko.sbs.de ([194.138.37.40]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1lvZhE-005nDm-2j for linux-arm-kernel@lists.infradead.org; Tue, 22 Jun 2021 06:15:41 +0000 Received: from mail2.sbs.de (mail2.sbs.de [192.129.41.66]) by gecko.sbs.de (8.15.2/8.15.2) with ESMTPS id 15M6FUwD013324 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 22 Jun 2021 08:15:30 +0200 Received: from [167.87.93.200] ([167.87.93.200]) by mail2.sbs.de (8.15.2/8.15.2) with ESMTP id 15M6FTtU011380; Tue, 22 Jun 2021 08:15:29 +0200 Subject: Re: [PATCH] serial: 8250: 8250_omap: Fix possible interrupt storm To: Vignesh Raghavendra , Tony Lindgren , Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, linux-omap@vger.kernel.org, Linux ARM Mailing List , linux-kernel@vger.kernel.org References: <20210511151955.28071-1-vigneshr@ti.com> From: Jan Kiszka Message-ID: <0ad948ac-f669-3d6d-5eca-4ca48d47d6a3@siemens.com> Date: Tue, 22 Jun 2021 08:15:29 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210621_231540_480028_262C9FCF X-CRM114-Status: GOOD ( 30.23 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 28.05.21 08:11, Vignesh Raghavendra wrote: > Hi, > > On 5/28/21 11:09 AM, Tony Lindgren wrote: >> Hi Greg, Vignesh & Jan, >> >> * Greg Kroah-Hartman [210513 14:17]: >>> On Tue, May 11, 2021 at 08:49:55PM +0530, Vignesh Raghavendra wrote: >>>> It is possible that RX TIMEOUT is signalled after RX FIFO has been >>>> drained, in which case a dummy read of RX FIFO is required to clear RX >>>> TIMEOUT condition. Otherwise, RX TIMEOUT condition is not cleared >>>> leading to an interrupt storm >>>> >>>> Cc: stable@vger.kernel.org >>> >>> How far back does this need to go? What commit id does this fix? What >>> caused this to just show up now vs. previously? > > Sorry, I missed this reply. Issue was reported on AM65x SoC with custom > test case from Jan Kiszka that stressed UART with rapid baudrate changes > from 9600 to 4M along with data transfer. > > Based on the condition that led to interrupt storm, I inferred it to > affect all SoCs with 8250 OMAP UARTs. But that seems thats not the best > idea as seen from OMAP3 regression. > > Greg, > > Could you please drop the patch? Very sorry for the inconvenience.. > >> >> I just noticed this causes the following regression in Linux next when >> pressing a key on uart console after boot at least on omap3. This seems >> to happen on serial_port_in(port, UART_RX) in the quirk handling. >> >> Vignesh, it seems this quirk needs some soc specific flag added to >> it maybe? Or maybe UART_OMAP_RX_LVL register is not available for >> all the SoCs? >> > > Yes indeed :( > >> I think it's best to drop this patch until the issues are resolved, >> also there are some open comments above that might be answered by >> limiting this quirk to a specific range of SoCs :) >> > > Oops, I did test patch AM33xx assuming its equivalent to OMAP3, but UART > IP is quite different. I will respin the patch making sure, workaround > applies only to AM65x and K3 SoCs. > > Regards > Vignesh > What's the status here for AM65x? The issue remains present on that platform, and I was hoping to see a quick follow up that limit the fix to that target. Jan -- Siemens AG, T RDA IOT Corporate Competence Center Embedded Linux _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel