Commit b166010f authored Jan 15, 2015 by Roger Tseng Committed by Lee Jones Jan 20, 2015

mfd: rtsx_usb: Fix runtime PM deadlock



sd_set_power_mode() in derived module drivers/mmc/host/rtsx_usb_sdmmc.c
acquires dev_mutex and then calls pm_runtime_get_sync() to make sure the
device is awake while initializing a newly inserted card. Once it is
called during suspending state and explicitly before rtsx_usb_suspend()
acquires the same dev_mutex, both routine deadlock and further hang the
driver because pm_runtime_get_sync() waits the pending PM operations.

Fix this by using an empty suspend method. mmc_core always turns the
LED off after a request is done and thus it is ok to remove the only
rtsx_usb_turn_off_led() here.

Cc: <stable@vger.kernel.org> # v3.16+
Fixes: 730876be ("mfd: Add realtek USB card reader driver")
Signed-off-by: Roger Tseng <rogerable@realtek.com>
[Lee: Removed newly unused variable]
Signed-off-by: Lee Jones <lee.jones@linaro.org>

parent f29ae369

drivers/mfd/rtsx_usb.c

+0 −12

Original line number	Diff line number	Diff line
		@@ -681,21 +681,9 @@ static void rtsx_usb_disconnect(struct usb_interface *intf)
		#ifdef CONFIG_PM
		static int rtsx_usb_suspend(struct usb_interface *intf, pm_message_t message)
		{
		struct rtsx_ucr *ucr =
		(struct rtsx_ucr *)usb_get_intfdata(intf);

		dev_dbg(&intf->dev, "%s called with pm message 0x%04x\n",
		__func__, message.event);

		/*
		* Call to make sure LED is off during suspend to save more power.
		* It is NOT a permanent state and could be turned on anytime later.
		* Thus no need to call turn_on when resunming.
		*/
		mutex_lock(&ucr->dev_mutex);
		rtsx_usb_turn_off_led(ucr);
		mutex_unlock(&ucr->dev_mutex);

		return 0;
		}

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