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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 AA261C07542 for ; Mon, 27 May 2019 07:48:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 888222075B for ; Mon, 27 May 2019 07:48:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726073AbfE0Hso (ORCPT ); Mon, 27 May 2019 03:48:44 -0400 Received: from mga11.intel.com ([192.55.52.93]:53221 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725869AbfE0Hsn (ORCPT ); Mon, 27 May 2019 03:48:43 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 May 2019 00:48:43 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,518,1549958400"; d="scan'208";a="178782694" Received: from ahunter-desktop.fi.intel.com (HELO [10.237.72.198]) ([10.237.72.198]) by fmsmga002.fm.intel.com with ESMTP; 27 May 2019 00:48:39 -0700 Subject: Re: Issue with Broadcom wireless in 5.2rc1 (was Re: [PATCH] mmc: sdhci: queue work after sdhci_defer_done()) To: Brian Masney , Arend Van Spriel Cc: Franky Lin , Hante Meuleman , Chi-Hsien Lin , Wright Feng , ulf.hansson@linaro.org, faiz_abbas@ti.com, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, Kalle Valo , linux-wireless@vger.kernel.org, brcm80211-dev-list.pdl@broadcom.com, brcm80211-dev-list@cypress.com, netdev@vger.kernel.org References: <20190524111053.12228-1-masneyb@onstation.org> <70782901-a9ac-5647-1abe-89c86a44a01b@intel.com> <20190524154958.GB16322@basecamp> <20190526122136.GA26456@basecamp> <20190526195819.GA29665@basecamp> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: Date: Mon, 27 May 2019 10:48:24 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190526195819.GA29665@basecamp> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org On 26/05/19 10:58 PM, Brian Masney wrote: > On Sun, May 26, 2019 at 08:42:21PM +0200, Arend Van Spriel wrote: >> On 5/26/2019 2:21 PM, Brian Masney wrote: >>> + Broadcom wireless maintainers >>> >>> On Fri, May 24, 2019 at 11:49:58AM -0400, Brian Masney wrote: >>>> On Fri, May 24, 2019 at 03:17:13PM +0300, Adrian Hunter wrote: >>>>> On 24/05/19 2:10 PM, Brian Masney wrote: >>>>>> WiFi stopped working on the LG Nexus 5 phone and the issue was bisected >>>>>> to the commit c07a48c26519 ("mmc: sdhci: Remove finish_tasklet") that >>>>>> moved from using a tasklet to a work queue. That patch also changed >>>>>> sdhci_irq() to return IRQ_WAKE_THREAD instead of finishing the work when >>>>>> sdhci_defer_done() is true. Change it to queue work to the complete work >>>>>> queue if sdhci_defer_done() is true so that the functionality is >>>>>> equilivent to what was there when the finish_tasklet was present. This >>>>>> corrects the WiFi breakage on the Nexus 5 phone. >>>>>> >>>>>> Signed-off-by: Brian Masney >>>>>> Fixes: c07a48c26519 ("mmc: sdhci: Remove finish_tasklet") >>>>>> --- >>>>>> [ ... ] >>>>>> >>>>>> drivers/mmc/host/sdhci.c | 2 +- >>>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>>> >>>>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c >>>>>> index 97158344b862..3563c3bc57c9 100644 >>>>>> --- a/drivers/mmc/host/sdhci.c >>>>>> +++ b/drivers/mmc/host/sdhci.c >>>>>> @@ -3115,7 +3115,7 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id) >>>>>> continue; >>>>>> if (sdhci_defer_done(host, mrq)) { >>>>>> - result = IRQ_WAKE_THREAD; >>>>>> + queue_work(host->complete_wq, &host->complete_work); >>>>> >>>>> The IRQ thread has a lot less latency than the work queue, which is why it >>>>> is done that way. >>>>> >>>>> I am not sure why you say this change is equivalent to what was there >>>>> before, nor why it fixes your problem. >>>>> >>>>> Can you explain some more? >>>> >>>> [ ... ] >>>> >>>> drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c calls >>>> sdio_claim_host() and it appears to never return. This is because SDHCI is using the IRQ thread to process the SDIO card interrupt (sdio_run_irqs()). When the card driver tries to use the card, it causes interrupts which deadlocks since c07a48c26519 ("mmc: sdhci: Remove finish_tasklet") has moved the tasklet processing to the IRQ thread. I would expect to be able to use the IRQ thread to complete requests, and it is desirable to do so because it is lower latency. Probably, SDHCI should use sdio_signal_irq() which queues a work item, and is what other drivers are doing. I will investigate some more and send a patch.