dwc2: gadget mode and timeout with GRSTCTL_CSFTRST

dwc2: gadget mode and timeout with GRSTCTL_CSFTRST

[Heiko Stuebner]

Hi,

right now we're experiencing strange behaviour with a dwc2 on Rockchip's
PX30 soc.

With a cable connected to the port, the configfs-snippet below seems to
work and at least creates a acm device on the host. Though I'm told that a
	 picocom -b 115200 /dev/ttyACM
sometimes works ok but also sometimes returns -EBUSY or hangs.
[But I guess that is a separate problem]

But if there is no cable connected when trying to do the configfs steps
we end up with
	dwc2_core_reset: HANG! Soft Reset timeout GRSTCTL GRSTCTL_CSFTRST
and no gadget gets configured.


So I guess to get a feeling for the issue, is this something to be
expected, or at least a known issue, with maybe a fix flying around
somewhere?

Or is this working on other dwc2 platforms correctly and is caused
by some other part talking to the dwc2 doing strange things?


Thanks
Heiko

-------- 8< ---- configfs snippet ------ >8 --------
cd /configfs/usb_gadget
mkdir g1
cd g1
echo "0x1d6d" > idVendor
echo "0x0104" > idProduct
mkdir strings/0x409
echo "0123456789" > strings/0x409/serialnumber
echo "Theobroma Systems" > strings/0x409/manufacturer
echo "Cobra Debug Serial" > strings/0x409/product

# create config
mkdir configs/c.1
mkdir configs/c.1/strings/0x409
echo "conf1" > configs/c.1/strings/0x409/configuration

# create function
mkdir functions/acm.usb0
ln -s functions/acm.usb0 configs/c.1

# activate new config
echo "" > UDC
echo "ff300000.usb" > UDC

Re: dwc2: gadget mode and timeout with GRSTCTL_CSFTRST

[Minas Harutyunyan]

Hi Heiko,


On 2/5/2020 6:37 PM, Heiko Stuebner wrote:
> Hi,
> 
> right now we're experiencing strange behaviour with a dwc2 on Rockchip's
> PX30 soc.
> 
> With a cable connected to the port, the configfs-snippet below seems to
> work and at least creates a acm device on the host. Though I'm told that a
> 	 picocom -b 115200 /dev/ttyACM
> sometimes works ok but also sometimes returns -EBUSY or hangs.
> [But I guess that is a separate problem]
> 
> But if there is no cable connected when trying to do the configfs steps
> we end up with
> 	dwc2_core_reset: HANG! Soft Reset timeout GRSTCTL GRSTCTL_CSFTRST
> and no gadget gets configured.
> 
Which timeout value set to wait GRSTCTL cleared? Does this commit 
applied: 6689f0f4bb14e "usb: dwc2: use a longer core rest timeout in 
dwc2_core_reset()"?
If yes, can you send debug log for above case.

Thanks,
Minas

> 
> So I guess to get a feeling for the issue, is this something to be
> expected, or at least a known issue, with maybe a fix flying around
> somewhere?
> 
> Or is this working on other dwc2 platforms correctly and is caused
> by some other part talking to the dwc2 doing strange things?
> 
> 
> Thanks
> Heiko
> 
> -------- 8< ---- configfs snippet ------ >8 --------
> cd /configfs/usb_gadget
> mkdir g1
> cd g1
> echo "0x1d6d" > idVendor
> echo "0x0104" > idProduct
> mkdir strings/0x409
> echo "0123456789" > strings/0x409/serialnumber
> echo "Theobroma Systems" > strings/0x409/manufacturer
> echo "Cobra Debug Serial" > strings/0x409/product
> 
> # create config
> mkdir configs/c.1
> mkdir configs/c.1/strings/0x409
> echo "conf1" > configs/c.1/strings/0x409/configuration
> 
> # create function
> mkdir functions/acm.usb0
> ln -s functions/acm.usb0 configs/c.1
> 
> # activate new config
> echo "" > UDC
> echo "ff300000.usb" > UDC
> 
> 
>