Re: PROBLEM: DWC3 USB 3.0 not working on Odroid-XU4 with Exynos 5422

[Felipe Balbi <balbi@kernel.org>]

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Hi,

Michael Niewöhner <linux@mniewoehner.de> writes:
> Hi Felipe,
> On Fri, 2016-10-07 at 22:26 +0200, Michael Niewöhner wrote:
>> Hi Felipe,
>> 
>> On Fr, 2016-10-07 at 10:42 +0300, Felipe Balbi wrote:
>> > Hi,
>> > 
>> > Michael Niewöhner <linux@mniewoehner.de> writes:
>> > > 
>> > > > 
>> > > > The clocks are same across working/non-working.
>> > > > Is it possible to bisect the commit that's causing hang for 4.8x ?
>> > > 
>> > > 
>> > > [c499ff71ff2a281366c6ec7a904c547d806cbcd1] usb: dwc3: core: re-factor init and exit paths
>> > > This patch causes both the hang on reboot and the lsusb hang.
>> > 
>> > How to reproduce? Why don't we see this on x86 and TI boards? I'm
>> > guessing this is failed bisection, as I can't see anything in that
>> > commit that would cause reboot hang. Also, that code path is *NOT*
>> > executed when you run lsusb.
>> > 
>> 
>> I've tested this procedure multiple times to be sure:
>> 
>> - checkout c499ff71, compile, boot the odroid
>> - run lsusb -v => lsusb hangs, can't terminate with ctrl-c
>> - hard reset, after boot run poweroff or reboot => board does not completely power off / reboot (see log below)
>> - revert c499ff71, mrproper, compile, boot the odroid
>> - run lsusb -v => shows full output, not hanging
>> - run reboot or poweroff => board powers off / reboots just fine
>> 
>> 
>> dmesg poweroff not working:
>> ...
>> [  120.733519] systemd-journald[144]: systemd-journald stopped as pid 144       
>> [  120.742663] systemd-shutdown[1]: Sending SIGKILL to remaining processes...   
>> [  120.769212] systemd-shutdown[1]: Unmounting file systems.                    
>> [  120.773713] systemd-shutdown[1]: Unmounting /sys/kernel/debug.               
>> [  120.827211] systemd-shutdown[1]: Unmounting /dev/mqueue.                     
>> [  121.081672] EXT4-fs (mmcblk1p2): re-mounted. Opts: (null)                    
>> [  121.091687] EXT4-fs (mmcblk1p2): re-mounted. Opts: (null)                    
>> [  121.095608] EXT4-fs (mmcblk1p2): re-mounted. Opts: (null)                    
>> [  121.101014] systemd-shutdown[1]: All filesystems unmounted.                  
>> [  121.106523] systemd-shutdown[1]: Deactivating swaps.                         
>> [  121.111585] systemd-shutdown[1]: All swaps deactivated.                      
>> [  121.116661] systemd-shutdown[1]: Detaching loop devices.                     
>> [  121.126395] systemd-shutdown[1]: All loop devices detached.                  
>> [  121.130525] systemd-shutdown[1]: Detaching DM devices.                       
>> [  121.135824] systemd-shutdown[1]: All DM devices detached.                    
>> [  121.166327] systemd-shutdown[1]: /lib/systemd/system-shutdown succeeded.     
>> [  121.171739] systemd-shutdown[1]: Powering off.
>> 
>> => at this point removing the sd card would show a message 
>> "removed mmc0" (not sure what the real message was...) so the board is not completely off.
>> 
>> 
>> dmesg poweroff working:
>> ...
>> [  120.733519] systemd-journald[144]: systemd-journald stopped as pid 144       
>> [  120.742663] systemd-shutdown[1]: Sending SIGKILL to remaining processes...   
>> [  120.769212] systemd-shutdown[1]: Unmounting file systems.                    
>> [  120.773713] systemd-shutdown[1]: Unmounting /sys/kernel/debug.               
>> [  120.827211] systemd-shutdown[1]: Unmounting /dev/mqueue.                     
>> [  121.081672] EXT4-fs (mmcblk1p2): re-mounted. Opts: (null)                    
>> [  121.091687] EXT4-fs (mmcblk1p2): re-mounted. Opts: (null)                    
>> [  121.095608] EXT4-fs (mmcblk1p2): re-mounted. Opts: (null)                    
>> [  121.101014] systemd-shutdown[1]: All filesystems unmounted.                  
>> [  121.106523] systemd-shutdown[1]: Deactivating swaps.                         
>> [  121.111585] systemd-shutdown[1]: All swaps deactivated.                      
>> [  121.116661] systemd-shutdown[1]: Detaching loop devices.                     
>> [  121.126395] systemd-shutdown[1]: All loop devices detached.                  
>> [  121.130525] systemd-shutdown[1]: Detaching DM devices.                       
>> [  121.135824] systemd-shutdown[1]: All DM devices detached.                    
>> [  121.166327] systemd-shutdown[1]: /lib/systemd/system-shutdown succeeded.     
>> [  121.171739] systemd-shutdown[1]: Powering off.
>> [  121.182331] rebo�
>> 
>> 
>> 
>> Best regards
>> Michael Niewöhner
>
>
> I did some more tests with next-20161016. Reverting / commenting out
> one part of your patch "solves" the lsusb hang, the reboot problem
> and also the "debounce failed" message. [1]
> Another "solution" is to call phy_power_off before phy_power_on. [2]
>
> Disclaimer: I have no idea what I was doing ;-) These were just some
> simple trial-and-error attempts that maybe help to find the real
> cause of the problems.
>
> [1]
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 7287a76..5ef589d 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -724,6 +724,7 @@ static int dwc3_core_init(struct dwc3 *dwc)
>  	/* Adjust Frame Length */
>  	dwc3_frame_length_adjustment(dwc);
>  
> +/*
>  	usb_phy_set_suspend(dwc->usb2_phy, 0);
>  	usb_phy_set_suspend(dwc->usb3_phy, 0);
>  	ret = phy_power_on(dwc->usb2_generic_phy);
> @@ -733,6 +734,7 @@ static int dwc3_core_init(struct dwc3 *dwc)
>  	ret = phy_power_on(dwc->usb3_generic_phy);
>  	if (ret < 0)
>  		goto err3;
> +*/
>  
>  	ret = dwc3_event_buffers_setup(dwc);
>  	if (ret) {
>
> [2]
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 7287a76..f6c8e13 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -726,6 +726,8 @@ static int dwc3_core_init(struct dwc3 *dwc)
>  
>         usb_phy_set_suspend(dwc->usb2_phy, 0);
>         usb_phy_set_suspend(dwc->usb3_phy, 0);
> +       phy_power_off(dwc->usb2_generic_phy);
> +       phy_power_off(dwc->usb3_generic_phy);

This looks like a PHY driver bug to me. Which PHY driver are you using?

-- 
balbi

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