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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 2380BC76192 for ; Thu, 18 Jul 2019 03:18:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E771E2173E for ; Thu, 18 Jul 2019 03:18:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563419924; bh=v0D3pV/YhXiqKMHowf+fL2GWT6Ro/wazB0YfW1Entuk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=tyGzt0s8NBZLBbU1lo4Bk1Ls0PusN228iYN7C1XdNYopPdIiecAAY3Bu2PNlnloVA erp1jzCkAszFpE2Z/l49Lrbj3nXomUOcD1NC/5AiDP3PeSIdkKAueoPWzgGSRee5RL 5SjspFFm4WVyS0E16IDI7rCsCvdsU2fAKEdNs7vA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391538AbfGRDMx (ORCPT ); Wed, 17 Jul 2019 23:12:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:47644 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391527AbfGRDMw (ORCPT ); Wed, 17 Jul 2019 23:12:52 -0400 Received: from localhost (115.42.148.210.bf.2iij.net [210.148.42.115]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 86F642077C; Thu, 18 Jul 2019 03:12:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563419572; bh=v0D3pV/YhXiqKMHowf+fL2GWT6Ro/wazB0YfW1Entuk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SSKPL2ZoqUJjvjWiRHlP/sYhZK+Q/i7YGvS0zIvSL1QnnXKPVE7kG+PE4bQOGTQss nEcWrhpytEZEpm6DiEYji3qN/F9DRJv9uRbM49KSKKiZ974N5b/BGt8XNSDsWDFZ/h Lqbb/AtnfqJEbPk2PJ75SV4AhAtAnx3YzwpQzrYQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Oliver Barta , Andy Shevchenko Subject: [PATCH 4.9 31/54] Revert "serial: 8250: Dont service RX FIFO if interrupts are disabled" Date: Thu, 18 Jul 2019 12:02:01 +0900 Message-Id: <20190718030051.844858216@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190718030048.392549994@linuxfoundation.org> References: <20190718030048.392549994@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Oliver Barta commit 3f2640ed7be838c3f05c0d2b0f7c7508e7431e48 upstream. This reverts commit 2e9fe539108320820016f78ca7704a7342788380. Reading LSR unconditionally but processing the error flags only if UART_IIR_RDI bit was set before in IIR may lead to a loss of transmission error information on UARTs where the transmission error flags are cleared by a read of LSR. Information are lost in case an error is detected right before the read of LSR while processing e.g. an UART_IIR_THRI interrupt. Signed-off-by: Oliver Barta Reviewed-by: Andy Shevchenko Fixes: 2e9fe5391083 ("serial: 8250: Don't service RX FIFO if interrupts are disabled") Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_port.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1814,8 +1814,7 @@ int serial8250_handle_irq(struct uart_po status = serial_port_in(port, UART_LSR); - if (status & (UART_LSR_DR | UART_LSR_BI) && - iir & UART_IIR_RDI) { + if (status & (UART_LSR_DR | UART_LSR_BI)) { if (!up->dma || handle_rx_dma(up, iir)) status = serial8250_rx_chars(up, status); }