On Tue, 26 May 2020 12:20:04 +0100 Steve McIntyre <st...@einval.com> wrote:
> On Sat, May 23, 2020 at 10:34:36AM +0900, Punit Agrawal wrote:
> >On Sat, May 23, 2020 at 1:54 AM Steve McIntyre <st...@einval.com> wrote:
> >>
> >> On Sat, May 23, 2020 at 01:15:37AM +0900, Punit Agrawal wrote:
> >
> >[...]
> >
> >> >To avoid needing any workarounds such as those discussed in earlier
> >> >replies, I looked at enabling the installer images to output on the
> >> >serial console by default. The attached simple change to the grub
> >> >configuration gives output on serial as well as connected monitor.
> >> >
> >> >The next issue that needs fixing is to update the kernel command line
> >> >to launch the installer on the serial console.
> >>
> >> I think few people have been bothered by this in the past - all the
> >> server machines I've used for years have had options for redirecting a
> >> VGA console to the serial port. Do you have one that doesn't?
> >
> >Actually, I was installing in "-nographic" VM rather than a server.
> >There are workarounds that allow me to continue earlier in the thread
> >(See #67, #68) but I was hoping to improve things so that it just
> >works.
> >
> >I was just surprised that it isn't possible to use the installer
> >without a VGA monitor (or a redirect on hardware that supports it) -
> >especially coming from arm64. There are a few other use cases that
> >will benefit from the serial support as well.
> >
> >Considering that it looks to be a configuration issue - do you think
> >it's worth enabling? Are there any downsides that I am missing?
>
> Possibly? I spent half an hour looking at things last week, but I
> don't have the time to look at this properly for a while myself. Other
> priorities...
Thanks for taking a look. Appreciate your comments.
>From looking at your feedback below, it seems (as of now) the issue
regarding enabling serial output in d-i grub is -
1. Feasibility (and the required changes)
2. While, not degrading behaviour for existing users
I completely agree and have tried to figure out 1. without regressing
existing other use cases.
> >From your patch, I'm not sure:
>
> a) you're unconditionally replacing colour choices
This is needed to enable text based grub menu on the serial console.
The display still shows the fancy image based splash / graphical
looking menu from before.
> b) you're setting up terminal_output only, what about terminal_input?
> (as mentioned in the info pages)
> c) do you need to have a "serial" command to enable serial ports
> (again, from the info page)?
I had both "serial --unit=0" and "terminal_input console gfxterm" in
an earlier local version of the patch (following the documentation).
But they got dropped in a bid to minimise the changes that add the
missing feature. I am not entirely sure why things work without both
of these to be honest.
But thinking back, it's best to stick to documented use to future
proof against grub updates. I will update the patch adding these back.
> d) is there any downside on machines without serial?
I did not notice any downsides to the normal (display connected) use
case in my testing.
I tested the following combination of display and serial using Qemu
i. Display only (no serial option passed to Qemu)
ii. Display and Serial connected ("-serial mon:stdio")
iii. Serial only ("-nographic -serial mon:stdio")
I'll post an updated patch (likely later today), adding the left out
configuration ("serial" and "terminal_input").
If it passes initial testing, we should consider merging into nightly
builds to get wider feedback and be quick to revert in case of
regression.
