On Wednesday, 28 July 2021 10:02:47 CEST Michael Stapelberg wrote: > Ben Hutchings <ben@decadent.org.uk> writes: > > On Fri, 2017-07-14 at 20:34 +0200, Sascha Silbe wrote: > >> Source: linux > >> Version: 4.11.6-1 > >> > >> on some amd64 systems no native or PCI(e) serial ports are available > >> resp. possible. USB serial adapters are the only option to get a > >> serial console for debugging boot problems in this case. > > > > I think this case is too unusual to make it worth building in all the > > USB stuff needed to make this work on all x86 systems. > > I’d like to respectfully ask you to reconsider this position. > > Over the years, more and more mainboards have dropped all support for > any onboard serial ports. Using a USB serial console is nowadays often > the only option for getting boot messages to another computer. > > To make the USB console work, I had to build my own Debian kernel with > the following options changed: > > CONFIG_USB=y > CONFIG_USB_SERIAL=y > CONFIG_USB_SERIAL_CONSOLE=y > > Given Debian’s popularity for server scenarios, I think we should make > troubleshooting easier and have USB serial consoles just work. > > Could you please enable CONFIG_USB_SERIAL_CONSOLE=y? $ grep -E "(CONFIG_USB|CONFIG_USB_SERIAL|CONFIG_USB_SERIAL_CONSOLE)=" /boot/config-5.18.0-1-amd64 CONFIG_USB=m CONFIG_USB_SERIAL=m In drivers/usb/serial/Kconfig at config USB_SERIAL_CONSOLE, I see this: depends on USB_SERIAL=y Can you check whether the following kernel config works? CONFIG_USB=m CONFIG_USB_SERIAL=y CONFIG_USB_SERIAL_CONSOLE=y Preferably only make the changes on the amd64 config, thus not globally. F.e. on my RPi and Rock64 (arm), I don't need USB_SERIAL_CONSOLE to have a working serial console (connected to the GPIO pins). usbserial.ko is 135K on my 5.18.0-1-amd64 kernel, so that's another aspect that needs to be evaluated. Note that I'm only trying to find the smallest change possible. I don't know whether these changes have other 'side affects'. I also have no idea whether it will change anything wrt being considered. IOW: you may be wasting your time. But I do see most/all peripherals disappearing, except USB and the 'wontfix' decision was from almost 5 years ago. USB serial consoles tend to be rather cheap and it (therefor) may also result in better bug reports on the kernel. Cheers, Diederik
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