Date: Tue, 15 Feb 2022 08:52:33 +1030 From: "Daniel O'Connor" <darius@dons.net.au> To: Archimedes Gaviola <archimedes.gaviola@gmail.com> Cc: mike@karels.net, freebsd-arm@freebsd.org Subject: Re: Raspberry Pi 4B does not detect devices in USB 3.0 Message-ID: <D9CA3262-2827-465F-9A3B-C200150EB77A@dons.net.au> In-Reply-To: <CAJFbk7ERFyf1DGP4E4=F295o7YLOUCcZxi0JpWZPoz52JhK_AA@mail.gmail.com> References: <CAJFbk7E=t4ezXVgTTGQdsxNbAEgUJfRU5Phk=gy4m2ovBMzhww@mail.gmail.com> <202112231500.1BNF0FgX014693@mail.karels.net> <CAJFbk7EAoit=e-14sg7YGHMtf7qWA5VjDgnnn4xt9tMERjt17Q@mail.gmail.com> <E3005D55-FE54-4911-89C7-1E017975A1CA@dons.net.au> <CAJFbk7FFtq9xQW9rWZM5Vx-wQ09B47zkwPWrjzLnbNfAFeCvhw@mail.gmail.com> <CAJFbk7ERFyf1DGP4E4=F295o7YLOUCcZxi0JpWZPoz52JhK_AA@mail.gmail.com>
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> On 14 Feb 2022, at 23:10, Archimedes Gaviola = <archimedes.gaviola@gmail.com> wrote: > I just tried my new RPI4 board and it seems to work fine the same as = my old board. I just observed that the problem is when my VFD (vacuum = fluorescent display) device is connected to either of the two USB 3.0 = ports, this device having uplcom(4) driver is not detected. I wonder if the VFD is causing interference - it likely has a high = voltage supply and those are notorious for generating electrical noise. > It's a Prolific USB-serial device having PL2303 chipset. However, when = plugged-in to USB 2.0 ports, this device is detected and functioning. I = can send characters with the echo command and redirect it to /dev/cuaU0 = for display without any problem. Other observations when this VFD device = is connected to either 3.0 ports, the 2.0 ports will not function i.e. = plugging-in any USB devices like my keyboard or my EMV reader. When this = device is also connected to either of the 2.0 ports, the other 2.0 port = is functioning for other USB devices while 3.0 ports are not. I attached = two dmesg outputs when the device is detected with 2.0 ports and = undetected with 3.0. I also include kldstat and usbdump. I would be curious if putting the VFD on a longer cable, or wrapping the = cable through a ferrite, or using an external hub fixes it. Any of those would give a bit more isolation between the VFD and USB3 = hardware. -- Daniel O'Connor "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum
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