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 locks and this isn't really working. As a hack for now I just push both handler into the threaded mode.
Reported-By: Michal Šmucr <[email protected]> Signed-off-by: Sebastian Andrzej Siewior <[email protected]> --- The "same thing" was reported against the iwlwifi driver (request_threaded_irq(…, iwl_pcie_isr, iwl_pcie_irq_handler, …) 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, void *dev_id) return isr ? IRQ_HANDLED : IRQ_NONE; } +#ifdef CONFIG_PREEMPT_RT_BASE +static irqreturn_t sdhci_rt_irq(int irq, void *dev_id) +{ + irqreturn_t ret; + + local_bh_disable(); + ret = sdhci_irq(irq, dev_id); + local_bh_enable(); + if (ret == IRQ_WAKE_THREAD) + ret = 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) } if (!device_may_wakeup(mmc_dev(host->mmc))) { - ret = request_threaded_irq(host->irq, sdhci_irq, - sdhci_thread_irq, IRQF_SHARED, - mmc_hostname(host->mmc), host); + ret = sdhci_req_irq(host); if (ret) return ret; } else { @@ -3253,8 +3276,7 @@ int sdhci_add_host(struct sdhci_host *host) sdhci_init(host, 0); - ret = request_threaded_irq(host->irq, sdhci_irq, sdhci_thread_irq, - IRQF_SHARED, mmc_hostname(mmc), host); + ret = sdhci_req_irq(host); if (ret) { pr_err("%s: Failed to request IRQ %d: %d\n", mmc_hostname(mmc), host->irq, ret); -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
