Raspberry Pi 4B with OpenBSD 6.7-current freezes or kernel panic with uplcom(4)

Previous Topic Next Topic
 
classic Classic list List threaded Threaded
3 messages Options
Reply | Threaded
Open this post in threaded view
|

Raspberry Pi 4B with OpenBSD 6.7-current freezes or kernel panic with uplcom(4)

Archimedes Gaviola
Hi,

I plugged my USB (bus powered) vacuum fluorescent display (VFD) pole device
and detected as uplcom(4) driver. After the device has been detected kernel
panic was observed or freezes the whole system. Please see attached
screenshot https://i.postimg.cc/sXSJyc4S/IMG-7820.jpg and dmesg for
details.

For now, the only way to prevent the issue is to shutdown my Raspberry Pi
4B system and then plug the VFD device. There is no problem with
OpenBSD-6.7 i386 release, plug and play works as expected.

uplcom0 at uhub2 port 4 configuration 1 interface 0 "Prolific Technology
Inc. USB-Serial Controller" rev 2.00/3.00 addr 7
ucom0 at uplcom0

Hardware: Raspberry Pi 4B
UEFI Firmware: UEFI v1.18
OpenBSD-current (arm64): August 27, 2020

Thanks and best regards,
Archimedes

dmesg_openbsd-6.7-arm64-current_uplcom-kernel-panic (8K) Download Attachment
Reply | Threaded
Open this post in threaded view
|

Re: Raspberry Pi 4B with OpenBSD 6.7-current freezes or kernel panic with uplcom(4)

Mark Kettenis
> From: Archimedes Gaviola <[hidden email]>
> Date: Tue, 6 Oct 2020 19:24:34 +0800
>
> Hi,
>
> I plugged my USB (bus powered) vacuum fluorescent display (VFD) pole device
> and detected as uplcom(4) driver. After the device has been detected kernel
> panic was observed or freezes the whole system. Please see attached
> screenshot https://i.postimg.cc/sXSJyc4S/IMG-7820.jpg and dmesg for
> details.
>
> For now, the only way to prevent the issue is to shutdown my Raspberry Pi
> 4B system and then plug the VFD device. There is no problem with
> OpenBSD-6.7 i386 release, plug and play works as expected.
>
> uplcom0 at uhub2 port 4 configuration 1 interface 0 "Prolific Technology
> Inc. USB-Serial Controller" rev 2.00/3.00 addr 7
> ucom0 at uplcom0
>
> Hardware: Raspberry Pi 4B
> UEFI Firmware: UEFI v1.18
> OpenBSD-current (arm64): August 27, 2020
>
> Thanks and best regards,
> Archimedes

Judging from your description of the device and the "impossible"
panic, I suspect this is a power issue.  The crash is typical for
situations where the voltage to the CPU and/or memory drops too low.

A better power supply might help, but it may be best to use an
externally powered USB hub instead.

Reply | Threaded
Open this post in threaded view
|

Re: Raspberry Pi 4B with OpenBSD 6.7-current freezes or kernel panic with uplcom(4)

Archimedes Gaviola
On Tue, Oct 6, 2020 at 7:59 PM Mark Kettenis <[hidden email]>
wrote:

> > From: Archimedes Gaviola <[hidden email]>
> > Date: Tue, 6 Oct 2020 19:24:34 +0800
> >
> > Hi,
> >
> > I plugged my USB (bus powered) vacuum fluorescent display (VFD) pole
> device
> > and detected as uplcom(4) driver. After the device has been detected
> kernel
> > panic was observed or freezes the whole system. Please see attached
> > screenshot https://i.postimg.cc/sXSJyc4S/IMG-7820.jpg and dmesg for
> > details.
> >
> > For now, the only way to prevent the issue is to shutdown my Raspberry Pi
> > 4B system and then plug the VFD device. There is no problem with
> > OpenBSD-6.7 i386 release, plug and play works as expected.
> >
> > uplcom0 at uhub2 port 4 configuration 1 interface 0 "Prolific Technology
> > Inc. USB-Serial Controller" rev 2.00/3.00 addr 7
> > ucom0 at uplcom0
> >
> > Hardware: Raspberry Pi 4B
> > UEFI Firmware: UEFI v1.18
> > OpenBSD-current (arm64): August 27, 2020
> >
> > Thanks and best regards,
> > Archimedes
>
> Judging from your description of the device and the "impossible"
> panic, I suspect this is a power issue.  The crash is typical for
> situations where the voltage to the CPU and/or memory drops too low.
>
> A better power supply might help, but it may be best to use an
> externally powered USB hub instead.
>

Hi Mark,

Thanks for your analysis and thoughts, I'll secure a USB hub with external
power and see if this issue still occurs.

Thanks and best regards,
Archimedes