Adam,

That change certainly makes it a lot better! Now it (ttyS0 configuration) gets 
to the same point as the hvc0 configuration.
I get the login: message, and a # prompt, but it will not take input. Maybe I'm 
missing a qemu flag?
Or a connection from cons to the vm in the cfg file?

So close. Both hvc0 and ttyS0 now display a #, but there is no input.

Thanks!

Richard



-----Original Message-----
From: Adam Lackorzynski <[email protected]> 
Sent: Monday, April 14, 2025 4:05 PM
To: Richard Clark <[email protected]>; 
[email protected]
Cc: Bud Wykoff <[email protected]>
Subject: Re: Linux console?

Hi Richard,

your dts has the 'l4vmm,vcon_cap = "uart";' enabled (not commented out), thus 
the 8250 UART emulation in uvmm looks for a "uart" capability which is not 
there and thus disables the virtual UART. Removing that line or commenting it 
out will make this work I believe as the standard capability will be used then.


Adam

On Mon Apr 14, 2025 at 11:57:32 +0000, Richard Clark wrote:
> Adam,
> 
> Yes the vm-basic.cfg is where I started.
> 
> I am attaching a tgz file with two directories showing the two 
> different outputs that I get when trying to run hvc0 and ttyS0. Included are 
> the config files, the ramdisk, and the dts as well.
> 
> 
> Richard
> 
> 
> -----Original Message-----
> From: Adam Lackorzynski <[email protected]>
> Sent: Monday, April 14, 2025 12:49 AM
> To: Richard Clark <[email protected]>; 
> [email protected]
> Cc: Bud Wykoff <[email protected]>
> Subject: Re: Linux console?
> 
> Hi Richard,
> 
> On Fri Apr 11, 2025 at 15:27:18 +0000, Richard Clark wrote:
> > L4Re,
> > 
> > I’ve been working with the examples and tweaking them for AMD64 
> > (QEMU), and I’ve managed to get linux up and booting, reading the 
> > ramdisk, and even spawning a login process which kicks off /bin/sh 
> > and displays a # prompt. And that’s great, but that’s all it does. I 
> > can’t get any input to it. That’s using the device hvc0. Of course 
> > uvmm complains that there is no virtual console and warns that it 
> > might not work, so the software is at least not surprised! 😊 But 
> > when I try to use the device ttyS0, linux stops printing even before 
> > the login process tries to run. I don’t get any errors, but also no 
> > output. And I can’t seem to run the IO server because then linux won’t load 
> > at all (something about out-of-memory).
> > 
> > I’m sure I’m missing some little piece of magic somewhere, but I 
> > can’t find any working examples. None of them have active logins (I 
> > had to add my own iniittab to the ramdisk). A little help connecting 
> > the cons service to my linux so I can get a real bash shell? Or 
> > running IO and connecting through that?
> 
> Did you try to run for example the "VM-basic" entry that is there? That is 
> supposed to be a minimal working example.
> Please also provide the output from the system you're getting, that is 
> helping understanding what's going on.
> 
> 
> Thanks, Adam

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