On Tue, Oct 6, 2020 at 7:59 PM Mark Kettenis <mark.kette...@xs4all.nl> wrote:
> > From: Archimedes Gaviola <archimedes.gavi...@gmail.com> > > 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
