Return-path: Received: from mail-ot0-f194.google.com ([74.125.82.194]:33025 "EHLO mail-ot0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753084AbdATQaI (ORCPT ); Fri, 20 Jan 2017 11:30:08 -0500 Subject: Re: [PATCH] rtlwifi: rtl8192x: Enabling and disabling hardware interrupts after enabling local irq flags To: Bharat Kumar Gogada , "chaoming_li@realsil.com.cn" , "linux-wireless@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: <1484820854-16719-1-git-send-email-bharatku@xilinx.com> <8520D5D51A55D047800579B094147198263CA86D@XAP-PVEXMBX02.xlnx.xilinx.com> Cc: "kvalo@codeaurora.org" , "netdev@vger.kernel.org" , Ravikiran Gummaluri From: Larry Finger Message-ID: <07fff87e-4dc2-f7b1-76f1-263be2410905@lwfinger.net> (sfid-20170120_173012_702244_B09CE471) Date: Fri, 20 Jan 2017 10:30:05 -0600 MIME-Version: 1.0 In-Reply-To: <8520D5D51A55D047800579B094147198263CA86D@XAP-PVEXMBX02.xlnx.xilinx.com> Content-Type: text/plain; charset=windows-1252; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 01/20/2017 08:14 AM, Bharat Kumar Gogada wrote: > > On 01/19/2017 04:14 AM, Bharat Kumar Gogada wrote: >>> -Realtek 8192CE chipset maintains local irq flags after enabling/disabling >>> hardware interrupts. >>> -Hardware interrupts are enabled before enabling the local irq >>> flags(these flags are being checked in interrupt handler), >>> leading to race condition on some RP, where the irq line between >>> bridge and GIC goes high at ASSERT_INTx and goes low only >>> at DEASSERT_INTx. In this kind of RP by the time ASSERT_INTx is seen >>> irq_enable flag is still set to false, resulting in continuous >>> interrupts seen by CPU as DEASSERT_INTx cannot be sent since >>> flag is still false and making CPU stall. >>> -Changing the sequence of setting these irq flags. >>> >>> Signed-off-by: Bharat Kumar Gogada >>> --- >> >> This patch should be enhanced with the smb_xx() calls as suggested by by Lino. >> >> The subject should be changed. I would suggest something like "rtlwifi: >> rtl8192ce: Prevent race condition when enabling interrupts", as it explains the >> condition you are preventing. >> >> The other PCI drivers also have the same problem. Do you want to prepare the >> patches, or should I do it? >> > Thanks Larry. Please send out the patches adding the above enhancements suggested by Lino. I have prepared a patch fixing all the drivers. By the way, what CPU hardware showed this problem? Larry