In D35146#798384, @archimedes.gaviola_gmail.com wrote:

In D35146#798321, @hselasky wrote:

I wonder why there is an overcurrent event happening in the first place ....

My theory is that overcurrent occurs due to USB port power pins first contact with the USB device (PL2303) power pins. There is an abrupt outgoing current happening during this first contact of pins and after some period it slows down and normalized since the power pins are already in contact with each other.

As a background, here's the Prolific PL2303 device that I'm talking about https://filebin.net/g8rj54rzkj5q7kd0, the device showing "VFD Display PD220" which is currently connected to one of the USB ports of my RPi 3B.

In D35146#798323, @hselasky wrote:

Hans, can you further explain this "overcurrent not set"? I'm reading the USB 2.0 specifications here http://sdpha2.ucsd.edu/Lab_Equip_Manuals/usb_20.pdf on the last paragraph on page 339 with continuation on page 340.

Did you find an answer?

In D35146#798321, @hselasky wrote:

I wonder why there is an overcurrent event happening in the first place ....

In D35146#798320, @hselasky wrote:

I see.

Can you upload the patch with context:

diff -U 999999 sys/dev/usb/usb_hub.c.orig sys/dev/usb/usb_hub.c > usb.diff

--HPS

Changes:

• usb_pause_mtx() function is placed after UHF_PORT_POWER.
• diff enabled in more context output (diff -U 999999)

In D35146#798139, @hselasky wrote:

I'll get back to you tomorrow. Not working today :-)

In D35146#796859, @hselasky wrote:

I suggest you add a counter which resets on overcurrent not set, and counts to 3 before giving up power on.

In D35146#796860, @archimedes.gaviola_gmail.com wrote:

In D35146#796859, @hselasky wrote:

I suggest you add a counter which resets on overcurrent not set, and counts to 3 before giving up power on.

We don't want to cause a fire :-)

Oh my... this is noted. Let me figure-out the code again and revise.

In D35146#796859, @hselasky wrote:

I suggest you add a counter which resets on overcurrent not set, and counts to 3 before giving up power on.

We don't want to cause a fire :-)

In D35146#796851, @hselasky wrote:

Please update your patch! There is an "update diff" selection in the "menu".

BTW: You should use:

usb_port_powerup_delay

from

usb_debug.h

And not the XXX_spec value.

Added sleep in the code before turning-on the power.