As a workaround I just: * removed "set tty fb0" from /etc/boot.conf * Commented the ligne beginning by "console" on /etc/ttys
I was able to get data arriving on UART RX using /dev/console, which was my goal. But there was another problem I noticed later, at reboot time, the u-boot was stuck at: Hit any key to stop autoboot Which I guess make sense since 1200 bauds data arriving on what is expected to be user input must be messing with the u-boot. I will just use additional hardware to make sure the signal arriving on UART RX is cut until the boot is finished. Thank you everybody. On Fri, Dec 22, 2023 at 08:00:35AM +0000, Miod Vallat wrote: > > > According to dmesg, Pi (at least 3b and 4) only have pluart, and no com. > > > > the com(4) is "brcm,bcm2835-aux-uart" > > > > no longer the console after: > > > > "date: 2019/11/17 06:03:39; author: jsg; state: Exp; lines: +9 -2; > > commitid: RNzxIO92MIKR4uhW; > > Use disable-bt overlay with raspberry pi so the pl011 will be used as > > console uart instead of the 'mini uart' a quirky 8250 alike which > > lacks flow control and break detection. By default the pl011 is used > > for bluetooth. The pins the console is on do not change. > > > > When com(4) takes over the console with the mini uart on rpi3 I see > > noise before output resumes and can't interact with the console after it > > has booted. With pluart(4) as console everything is fine." > > Yes, but what I mean is that com(4) no longer attaches anywhere, thus > the hijacking logic in pluart will not work. > > Also, this logic is only run when pluart is the console, so when the > system is configured to use a glass console, as is the case for the OP, > there would be no way to use the UART without giving it its own device > node. >
