Re: FTDI serial console support?

[Petter Gustad]

From: Daniel Kiper <address@hidden>
Subject: Re: FTDI serial console support?
Date: Fri, 18 May 2018 13:55:55 +0200

> On Fri, May 18, 2018 at 01:01:41PM +0200, Petter Gustad wrote:
>> From: Daniel Kiper <address@hidden>
>> Subject: Re: FTDI serial console support?
>> Date: Wed, 16 May 2018 11:32:19 +0200
>>
>> > On Wed, May 16, 2018 at 06:21:17AM +0200, Petter Gustad wrote:
>> >> From: Daniel Kiper <address@hidden>
>> >> Subject: Re: FTDI serial console support?
>> >> Date: Tue, 15 May 2018 22:00:06 +0200
>> >>
>> >> > On Fri, May 11, 2018 at 03:55:36PM +0200, Petter Gustad wrote:
>> >> >>
>> >> >> Is there a way to specify a FTDI based serial console using
>> >> >> GRUB_TERMINAL, GRUB_SERIAL_COMMAND, or some other variable? If yes,
>> >> >> what is the syntax?
>> >> >>
>> >> >> BTW my serial port adapter matches the vendor id and device id given
>> >> >> in grub-core/bus/usb/serial/ftdi.c:
>> >> >>
>> >> >> Bus 001 Device 008: ID 0403:6001 Future Technology Devices 
>> >> >> International, Ltd FT232 Serial (UART) IC
>> >> >
>> >> > Have you tried usbserial_ftdi, e.g. GRUB_TERMINAL=usbserial_ftdi?
>> >> > Just guessing...
>> >>
>> >> Yes, I tried (as I found the "usbserial_ftdi" string in the source)
>> >> the but grub-mkconfig does not accecpt it:
>> >>
>> >> grub-mkconfig -o /boot/grub/grub.cfg
>> >> Invalid output terminal "usbserial_ftdi"
>> >>
>> >> Currently I have this:
>> >>
>> >> GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=ttyUSB0,115200n8"
>> >> #GRUB_TERMINAL="console serial"
>> >> GRUB_TERMINAL="serial"
>> >> GRUB_SERIAL_COMMAND="usbserial_ftdi --speed=115200 --unit=0 --word=8 
>> >> --parity=no --stop=1"
>> >>
>> >> But this does not seem to work either, even though I do get console
>> >> output on my USB serial after the kernel has loaded (due to
>> >> GRUB_CMDLINE_LINUX being passed to the kernel), e.g. I can do "echo
>> >> hello > /dev/console" and read "hello" on the USB serial output. When
>> >> I do a "reboot" I observe messages about unmounting filesystems etc.
>> >>
>> >> I was hoping to be able to select kernels and options in grub using
>> >> the USB serial line.
>> >
>> > Please take a look here:
>> >   https://www.coreboot.org/GRUB2#On_a_USB_serial_or_USB_debug_adapter
>> >
>> > I hope that helps.
>>
>> Thank you for the link.
>>
>> Unfortunately, it seems like my system can't access the hard disk
>> after running "insmod ehci" despite doing "insmod nativedisk" first.
>> Some of subsequent insmod commands will fail when accessing the disk
>> and I'm not able to boot linux either.
> 
> Could you just do "insmod usbserial_ftdi"? There is a chance that it
> will pull in all needed dependencies without breaking disk access.

Thanks. Only "insmod usbserial_ftdi" does work in the sense that it
will not break disk access. I also managed to load grub using PXE/tftp
where I was not dependend upon disk access.

But in both cases it does not work like in the coreboot URL above.
After do insmod on usbserial_ftdi and usbserial_usbdebug the
terminal_output command will only return console as its active output
terminal. It will list serial_* as available output terminals, but I
can't select usb0, usb1, etc as argument to the serial command.

Best regards
//Petter