[PATCH 2/2 v2] mmc/sdhci-acpi: enable sdhci-acpi device to suspend/resume asynchronously

[Fu, Zhonghui]

This patch enables sdhci-acpi devices to suspend/resume asynchronously.
This will improve system suspend/resume speed. After enabling the
sdhci-acpi devices and all their child devices to suspend/resume
asynchronously on ASUS T100TA, the system suspend-to-idle time is
reduced from 1645ms to 1089ms, and the system resume time is reduced
from 940ms to 908ms.

Signed-off-by: Zhonghui Fu <zhonghui.fu@xxxxxxxxxxxxxxx>
---
Changes in v2:
- Update commit message

 drivers/mmc/host/sdhci-acpi.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c
index f6047fc..3d27f2d 100644
--- a/drivers/mmc/host/sdhci-acpi.c
+++ b/drivers/mmc/host/sdhci-acpi.c
@@ -388,6 +388,8 @@ static int sdhci_acpi_probe(struct platform_device *pdev)
 		pm_runtime_enable(dev);
 	}
 
+	device_enable_async_suspend(dev);
+
 	return 0;
 
 err_free:
-- 1.7.1