From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian Masney Subject: Re: Issue with Broadcom wireless in 5.2rc1 (was Re: [PATCH] mmc: sdhci: queue work after sdhci_defer_done()) Date: Mon, 27 May 2019 08:50:26 -0400 Message-ID: <20190527125026.GA4272@basecamp> References: <20190524111053.12228-1-masneyb@onstation.org> <70782901-a9ac-5647-1abe-89c86a44a01b@intel.com> <20190524154958.GB16322@basecamp> <20190526122136.GA26456@basecamp> <20190526195819.GA29665@basecamp> <20190527093711.GA853@basecamp> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Adrian Hunter Cc: Arend Van Spriel , 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 List-Id: linux-mmc@vger.kernel.org On Mon, May 27, 2019 at 03:08:07PM +0300, Adrian Hunter wrote: > On 27/05/19 12:37 PM, Brian Masney wrote: > > On Sun, May 26, 2019 at 03:58:19PM -0400, Brian Masney wrote: > >> I attached a patch that shows how I was able to determine what had > >> already claimed the host. > > On Mon, May 27, 2019 at 10:48:24AM +0300, Adrian Hunter wrote: > >> 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. > > Please try the patch below: > > From: Adrian Hunter > Date: Mon, 27 May 2019 14:45:55 +0300 > Subject: [PATCH] mmc: sdhci: Fix SDIO IRQ thread deadlock > > Since commit c07a48c26519 ("mmc: sdhci: Remove finish_tasklet"), the IRQ > thread might be used to complete requests, but the IRQ thread is also used > to process SDIO card interrupts. This can cause a deadlock when the SDIO > processing tries to access the card since that would also require the IRQ > thread. Change SDHCI to use sdio_signal_irq() to schedule a work item > instead. That also requires implementing the ->ack_sdio_irq() mmc host op. > > Signed-off-by: Adrian Hunter > Fixes: c07a48c26519 ("mmc: sdhci: Remove finish_tasklet") Yes, this fixes the issue for me. You can add my: Reported-by: Brian Masney Tested-by: Brian Masney Thanks, Brian