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Commit b6ad726e authored by Ulf Hansson's avatar Ulf Hansson Committed by Chris Ball
Browse files

mmc: core: Prevent too long response times for suspend 



While trying to suspend the mmc host there could still be
ongoing requests that we need to wait for. At the same time
a device driver must respond to a suspend request rather quickly.

Instead of potentially wait "forever" by claiming the host we now
"try" to claim the host instead. If it fails, -EBUSY is returned.

Signed-off-by: default avatarUlf Hansson <ulf.hansson@stericsson.com>
Reviewed-by: default avatarSujit Reddy Thumma <sthumma@codeaurora.org>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent b4625dab

drivers/mmc/core/core.c

+27 −15
Original line number Diff line number Diff line
@@ -2294,6 +2294,14 @@ int mmc_suspend_host(struct mmc_host *host) 


	mmc_bus_get(host);

	if (host->bus_ops && !host->bus_dead) {



		/*

		 * A long response time is not acceptable for device drivers

		 * when doing suspend. Prevent mmc_claim_host in the suspend

		 * sequence, to potentially wait "forever" by trying to

		 * pre-claim the host.

		 */

		if (mmc_try_claim_host(host)) {

			if (host->bus_ops->suspend)

				err = host->bus_ops->suspend(host);

			if (err == -ENOSYS || !host->bus_ops->resume) {
@@ -2310,6 +2318,10 @@ int mmc_suspend_host(struct mmc_host *host) 
				host->pm_flags = 0;

				err = 0;

			}

			mmc_do_release_host(host);

		} else {

			err = -EBUSY;

		}

	}

	mmc_bus_put(host);