From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Andrzej Siewior Subject: [RT PATCH] mmc: sdhci: don't provide hard irq handler Date: Thu, 26 Feb 2015 12:29:26 +0100 Message-ID: <20150226112925.GC12992@linutronix.de> References: <54EC487F.8020109@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-rt-users@vger.kernel.org, linux-mmc@vger.kernel.org, Chris Ball To: Michal =?utf-8?B?xaBtdWNy?= Return-path: Content-Disposition: inline In-Reply-To: <54EC487F.8020109@gmail.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org the sdhci code provides both irq handlers: the primary and the thread handler. Initially it was meant for the primary handler to be very short. The result is not that on -RT we have the primrary handler grabing lock= s and this isn't really working. As a hack for now I just push both handler into the threaded mode. Reported-By: Michal =C5=A0mucr Signed-off-by: Sebastian Andrzej Siewior --- The "same thing" was reported against the iwlwifi driver (request_threaded_irq(=E2=80=A6, iwl_pcie_isr, iwl_pcie_irq_handler, =E2= =80=A6) and they managed to rework it and not do anything that would break -RT in their primary handler. Besides sdhci there are a few others drivers in the same tree doing similar things. I'm not sure what to do here in general. Motivating upstream maintainer to rework their code or introducing IRQF_RT_SAFE and for others doing the conversation like in the patch below. Michal: This is untested but should fix the issue, reported. drivers/mmc/host/sdhci.c | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 023c2010cd75..bcde53774bc9 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -2565,6 +2565,31 @@ static irqreturn_t sdhci_thread_irq(int irq, voi= d *dev_id) return isr ? IRQ_HANDLED : IRQ_NONE; } =20 +#ifdef CONFIG_PREEMPT_RT_BASE +static irqreturn_t sdhci_rt_irq(int irq, void *dev_id) +{ + irqreturn_t ret; + + local_bh_disable(); + ret =3D sdhci_irq(irq, dev_id); + local_bh_enable(); + if (ret =3D=3D IRQ_WAKE_THREAD) + ret =3D sdhci_thread_irq(irq, dev_id); + return ret; +} +#endif + +static int sdhci_req_irq(struct sdhci_host *host) +{ +#ifdef CONFIG_PREEMPT_RT_BASE + return request_threaded_irq(host->irq, NULL, sdhci_rt_irq, + IRQF_SHARED, mmc_hostname(host->mmc), host); +#else + return request_threaded_irq(host->irq, sdhci_irq, sdhci_thread_irq, + IRQF_SHARED, mmc_hostname(host->mmc), host); +#endif +} + /*********************************************************************= ********\ * = * * Suspend/resume = * @@ -2632,9 +2657,7 @@ int sdhci_resume_host(struct sdhci_host *host) } =20 if (!device_may_wakeup(mmc_dev(host->mmc))) { - ret =3D request_threaded_irq(host->irq, sdhci_irq, - sdhci_thread_irq, IRQF_SHARED, - mmc_hostname(host->mmc), host); + ret =3D sdhci_req_irq(host); if (ret) return ret; } else { @@ -3253,8 +3276,7 @@ int sdhci_add_host(struct sdhci_host *host) =20 sdhci_init(host, 0); =20 - ret =3D request_threaded_irq(host->irq, sdhci_irq, sdhci_thread_irq, - IRQF_SHARED, mmc_hostname(mmc), host); + ret =3D sdhci_req_irq(host); if (ret) { pr_err("%s: Failed to request IRQ %d: %d\n", mmc_hostname(mmc), host->irq, ret); --=20 2.1.4