Processing of SDIO IRQs must obviously be prevented while the card is system suspended, otherwise we may end up trying to communicate with an uninitialized SDIO card.
Reports throughout the years shows that this is not only a theoretical problem, but a real issue. So, let's finally fix this problem, by keeping track of the state for the card and bail out before processing the SDIO IRQ, in case the card is suspended.
Cc: stable@vger.kernel.org Reported-by: Douglas Anderson dianders@chromium.org Signed-off-by: Ulf Hansson ulf.hansson@linaro.org ---
This has only been compile tested so far, any help for real test on HW is greatly appreciated.
Note that, this is only the initial part of what is needed to make power management of SDIO card more robust, but let's start somewhere and continue to improve things.
The next step I am looking at right now, is to make sure the SDIO IRQ is turned off during system suspend, unless it's supported as a system wakeup (and enabled to be used).
--- drivers/mmc/core/sdio.c | 7 +++++++ drivers/mmc/core/sdio_irq.c | 4 ++++ 2 files changed, 11 insertions(+)
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c index d1aa1c7577bb..9951295d3220 100644 --- a/drivers/mmc/core/sdio.c +++ b/drivers/mmc/core/sdio.c @@ -937,6 +937,10 @@ static int mmc_sdio_pre_suspend(struct mmc_host *host) */ static int mmc_sdio_suspend(struct mmc_host *host) { + /* Prevent processing of SDIO IRQs in suspended state. */ + mmc_card_set_suspended(host->card); + cancel_delayed_work_sync(&host->sdio_irq_work); + mmc_claim_host(host);
if (mmc_card_keep_power(host) && mmc_card_wake_sdio_irq(host)) @@ -985,6 +989,9 @@ static int mmc_sdio_resume(struct mmc_host *host) err = sdio_enable_4bit_bus(host->card); }
+ /* Allow SDIO IRQs to be processed again. */ + mmc_card_clr_suspended(host->card); + if (!err && host->sdio_irqs) { if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) wake_up_process(host->sdio_irq_thread); diff --git a/drivers/mmc/core/sdio_irq.c b/drivers/mmc/core/sdio_irq.c index 931e6226c0b3..9f54a259a1b3 100644 --- a/drivers/mmc/core/sdio_irq.c +++ b/drivers/mmc/core/sdio_irq.c @@ -34,6 +34,10 @@ static int process_sdio_pending_irqs(struct mmc_host *host) unsigned char pending; struct sdio_func *func;
+ /* Don't process SDIO IRQs if the card is suspended. */ + if (mmc_card_suspended(card)) + return 0; + /* * Optimization, if there is only 1 function interrupt registered * and we know an IRQ was signaled then call irq handler directly.