On 03/27/2015 02:15 PM, Ulf Hansson wrote:
Currently those host drivers which have deployed runtime PM, deals with the runtime PM reference counting entirely by themselves. Since host drivers don't know when the core will send the next request through some of the host_ops callbacks, they need to handle runtime PM get/put between each an every request. In quite many cases this has some negative effects, since it leads to a high frequency of scheduled runtime PM suspend operations. That due to the runtime PM reference count will normally reach zero in-between every request. We can decrease that frequency, by enabling the core to deal with runtime PM reference counting of the host device. Since the core often knows that it will send a seqeunce of requests, it makes sense for it to keep a runtime PM reference count during these periods. More exactly, let's increase the runtime PM reference count by invoking pm_runtime_get_sync() from __mmc_claim_host(). Restore that action by invoking pm_runtime_mark_last_busy() and pm_runtime_put_autosuspend() in mmc_release_host(). In this way a runtime PM reference count will be kept during the complete cycle of a claim -> release host. Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> --- drivers/mmc/core/core.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 709ada9..c296bc0 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -897,6 +897,7 @@ int __mmc_claim_host(struct mmc_host *host, atomic_t *abort) DECLARE_WAITQUEUE(wait, current); unsigned long flags; int stop; + bool pm = false; might_sleep(); @@ -916,13 +917,18 @@ int __mmc_claim_host(struct mmc_host *host, atomic_t *abort) host->claimed = 1; host->claimer = current; host->claim_cnt += 1; + if (host->claim_cnt == 1) + pm = true; } else wake_up(&host->wq); spin_unlock_irqrestore(&host->lock, flags); remove_wait_queue(&host->wq, &wait); + + if (pm) + pm_runtime_get_sync(mmc_dev(host)); + return stop; } - EXPORT_SYMBOL(__mmc_claim_host); /** @@ -947,6 +953,8 @@ void mmc_release_host(struct mmc_host *host) host->claimer = NULL; spin_unlock_irqrestore(&host->lock, flags); wake_up(&host->wq); + pm_runtime_mark_last_busy(mmc_dev(host)); + pm_runtime_put_autosuspend(mmc_dev(host)); } } EXPORT_SYMBOL(mmc_release_host);
Acked-by: Konstantin Dorfman <kdorfman@xxxxxxxxxxxxxx> -- Qualcomm Israel, on behalf of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
