> On Sun, 15 Apr 2012, Sujit Reddy Thumma wrote:
>
>> Hi Nicolas,
>>
>> >
>> > Commit 06e8935feb "optimized SDIO IRQ handling for single irq"
>> > introduced some spurious calls to SDIO function interrupt handlers,
>> > such as when the SDIO IRQ thread is started, or the safety check
>> > performed upon a system resume. Let's add a flag to perform the
>> > optimization only when a real interrupt is signaled by the host
>> > driver and we know there is no point confirming it.
>> >
>>
>> Thanks for putting up formal patch.
>>
>> > Reported-by: Sujit Reddy Thumma <sthu...@codeaurora.org>
>> > Signed-off-by: Nicolas Pitre <n...@linaro.org>
>> > Cc: sta...@kernel.org
>> >
>> > diff --git a/drivers/mmc/core/sdio_irq.c b/drivers/mmc/core/sdio_irq.c
>> > index f573e7f9f7..3d8ceb4084 100644
>> > --- a/drivers/mmc/core/sdio_irq.c
>> > +++ b/drivers/mmc/core/sdio_irq.c
>> > @@ -28,18 +28,20 @@
>> >
>> > #include "sdio_ops.h"
>> >
>> > -static int process_sdio_pending_irqs(struct mmc_card *card)
>> > +static int process_sdio_pending_irqs(struct mmc_host *host)
>> > {
>> > + struct mmc_card *card = host->card;
>> > int i, ret, count;
>> > unsigned char pending;
>> > struct sdio_func *func;
>> >
>> > /*
>> > * Optimization, if there is only 1 function interrupt registered
>> > - * call irq handler directly
>> > + * and we know an IRQ was signaled then call irq handler directly.
>> > + * Otherwise do the full probe.
>> > */
>> > func = card->sdio_single_irq;
>> > - if (func) {
>> > + if (func && host->sdio_irq_pending) {
>> > func->irq_handler(func);
>> > return 1;
>> > }
>> > @@ -116,7 +118,8 @@ static int sdio_irq_thread(void *_host)
>> > ret = __mmc_claim_host(host, &host->sdio_irq_thread_abort);
>> > if (ret)
>> > break;
>> > - ret = process_sdio_pending_irqs(host->card);
>> > + ret = process_sdio_pending_irqs(host);
>> > + host->sdio_irq_pending = false;
>> > mmc_release_host(host);
>> >
>> > /*
>> > diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
>> > index ee2b0363c0..557aa4cd66 100644
>> > --- a/include/linux/mmc/host.h
>> > +++ b/include/linux/mmc/host.h
>> > @@ -323,6 +323,7 @@ struct mmc_host {
>> >
>> > unsigned int sdio_irqs;
>> > struct task_struct *sdio_irq_thread;
>> > + bool sdio_irq_pending;
>> > atomic_t sdio_irq_thread_abort;
>> >
>> > mmc_pm_flag_t pm_flags; /* requested pm features */
>> > @@ -378,6 +379,7 @@ extern int mmc_cache_ctrl(struct mmc_host *, u8);
>> > static inline void mmc_signal_sdio_irq(struct mmc_host *host)
>> > {
>> > host->ops->enable_sdio_irq(host, 0);
>> > + host->sdio_irq_pending = true;
>> > wake_up_process(host->sdio_irq_thread);
>> > }
>>
>> In this case probably we need to add the following:
>> @@ -946,8 +946,11 @@ static int mmc_sdio_resume(struct mmc_host *host)
>> }
>> }
>>
>> - if (!err && host->sdio_irqs)
>> - mmc_signal_sdio_irq(host);
>> + if (!err && host->sdio_irqs) {
>> + host->ops->enable_sdio_irq(host, 0);
>> + wake_up_process(host->sdio_irq_thread);
>> + }
>
> The call to enable_sdio_irq() is probably redundant. Only
> wake_up_process() should be sufficient.
>
True, I was wondering if we really need to wakeup sdio_irq_thread here. If
there is a pending interrupt is it not the host driver supposed to wake it
up or do you think it is needed for hosts that don't have CAP_SDIO_IRQ
set?
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