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mmc: core: Prevent too long response times for suspend

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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: Ulf Hansson <ulf.hansson@stericsson.com>
Reviewed-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Ulf Hansson 2011-10-13 16:03:58 +02:00 committed by Chris Ball
parent b4625dab2c
commit b6ad726e3f
1 changed files with 27 additions and 15 deletions
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42
drivers/mmc/core/core.c
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@ -2294,21 +2294,33 @@ int mmc_suspend_host(struct mmc_host *host)
mmc_bus_get(host);
if (host->bus_ops && !host->bus_dead) {
if (host->bus_ops->suspend)
err = host->bus_ops->suspend(host);
if (err == -ENOSYS || !host->bus_ops->resume) {
/*
* We simply "remove" the card in this case.
* It will be redetected on resume.
*/
if (host->bus_ops->remove)
host->bus_ops->remove(host);
mmc_claim_host(host);
mmc_detach_bus(host);
mmc_power_off(host);
mmc_release_host(host);
host->pm_flags = 0;
err = 0;
/*
* 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) {
/*
* We simply "remove" the card in this case.
* It will be redetected on resume.
*/
if (host->bus_ops->remove)
host->bus_ops->remove(host);
mmc_claim_host(host);
mmc_detach_bus(host);
mmc_power_off(host);
mmc_release_host(host);
host->pm_flags = 0;
err = 0;
}
mmc_do_release_host(host);
} else {
err = -EBUSY;
}
}
mmc_bus_put(host);