Re: resetting a usb com port?

Greg Troxel wrote:
> [email protected] (MLH) writes:
> 
> > I am programming some esp32s and every now and then the port locks up from
> > an error and I can't find a way to reset it properly.
> >
> > For example:
> >
> > [ 651173.2591532] uchcom0 at uhub1 port 9
> > [ 651173.2591532] uchcom0: QinHeng Electronics (0x1a86) USB Serial (0x7523), rev 1.10/2.64, addr 3
> > [ 651173.2691535] ucom0 at uchcom0
> > [ 651197.0392490] ucom0: detached
> > [ 651197.0392490] uchcom0: detached
> > [ 651197.0392490] uchcom0: at uhub1 port 9 (addr 3) disconnected
> > [ 651204.6892798] uhub1: device problem, disabling port 9
> > [ 651246.6894490] uhub1: device problem, disabling port 9
> > [ 651247.2094511] uhub1: device problem, disabling port 9
> >
> > Is there a way to reset ucom0 without having to reboot ?
> 
> ucom0 is surely not the problem.  It's a logical device attached to
> uchcom0.
> 
> In the above sequence, did you unplug thecable at 651197?  What happened
> at 651204?  Was that plugging in a different ESP32?

I think the esp32s serail port is messed up somehow. Sometimes I
can talk to it and sometimes not but I can't reprogram it. I am
trying to determine what is wrong with it.  The above sequence is
all from when I plugged it in and then unplug it (the last line,
I think).

> My impression is that the problem is the hub (and specifically the port
> on it), and that even unplugging and replugging the device will not
> help.
> 
> I think I've been able to unplug a hub (e.g. thinkpad keyboard) and have
> that hub replugged and be ok.  You might try interposing a hub and on
> flakiness, unplug everything from the hub, unplug the hub, wait 5s, plug
> back in.
> 
> Did you try plugging the cable into a different port?

No response when I tried to plug it into another usb port, however, plugging
a hub in worked:

[ 730330.9162374] uhub4 at uhub1 port 10: GenesysLogic (0x05e3) USB2.1 Hub (0x0610), class 9/0, rev 2.10/6.56, addr 7
[ 730330.9162374] uhub4: single transaction translator
[ 730331.6662392] uhub5 at uhub4 port 4: GenesysLogic (0x05e3) USB2.1 Hub (0x0610), class 9/0, rev 2.10/6.56, addr 8
[ 730331.6662392] uhub5: single transaction translator
[ 730472.0466106] uchcom0 at uhub4 port 1
[ 730472.0466106] uchcom0: QinHeng Electronics (0x1a86) USB Serial (0x7523), rev 1.10/2.64, addr 10

Thanks!!