[PATCH 1/2] mfd: rtsx_usb: Fix runtime PM deadlock

[Roger Tseng]

On Mon, 2015-01-19 at 09:45 +0000, Lee Jones wrote:
> On Thu, 15 Jan 2015, Roger Tseng wrote:
> 
> > 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 at vger.kernel.org> # v3.16+
> > Fixes: 730876be2566 ("mfd: Add realtek USB card reader driver")
> > Signed-off-by: Roger Tseng <rogerable at realtek.com>
> > ---
> >  drivers/mfd/rtsx_usb.c | 9 ---------
> >  1 file changed, 9 deletions(-)
> 
> Applied, thanks.
> 
I'm sorry but build bot from Intel just reported me that I forgot to
delete an unused variable "ucr" between two commits. My bad.

Do I have a chance to send v2?

> > diff --git a/drivers/mfd/rtsx_usb.c b/drivers/mfd/rtsx_usb.c
> > index dbdd0faeb6ce..076694126e5d 100644
> > --- a/drivers/mfd/rtsx_usb.c
> > +++ b/drivers/mfd/rtsx_usb.c
> > @@ -687,15 +687,6 @@ static int rtsx_usb_suspend(struct usb_interface *intf, pm_message_t message)
> >  	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;
> >  }
> >  
> 

-- 
Best regards,
Roger Tseng