[coreboot] alix.2c3 stops at mainboard_pre_payload: done

Roman Yeryomin rj at tc.lv
Mon Oct 13 10:27:50 CEST 2008


On Monday 13 October 2008 03:01:35 Peter Stuge wrote:
> Hi Roman,
>
> Roman Yeryomin wrote:
> > >>> on system with native bios (tinybios):
> > >>> cat /proc/tty/driver/serial
> > >>> serinfo:1.0 driver revision:
> > >>> 0: uart:16550A port:000003F8 irq:4 tx:945 rx:15 RTS|CTS|DTR|DSR|CD
> > >>> 1: uart:16550A port:000002F8 irq:3 tx:0 rx:0 CTS|DSR|CD
> > >>>
> > >>> but on system with coreboot:
> > >>> cat /proc/tty/driver/serial
> > >>> serinfo:1.0 driver revision:
> > >>> 0: uart:NS16550A port:000003F8 irq:4 tx:0 rx:0 RTS|DTR
> > >>> 1: uart:unknown port:000002F8 irq:3
>
> Did I overlook this message on the the list? If it wasn't sent to the
> list, please keep in mind that it's nicer both for you and for others
> after you to keep discussion on the list, for you because you may get
> quicker replies and for others because the solutions are archived.

I understand...
didn't look at the TO: address when sending email

> What I find most interesting about the output above is how uart 1 is
> identified differently when starting with coreboot. It would be good
> to find out why.

yes, that's the main question I think

> > >> OK, this is kind of the problem I remember. If you have time go into
> > >> the kernel, IIRC, there is a test for some modem signal and the device
> > >> is not available otherwise. I am sorry to be so fuzzy but this was
> > >> seven years ago. It was a weird problem.
> > >
> > > you think this is kernel problem?
>
> I don't think serial control signals is the source of your problems.
> Even if they are, the problem is not in the kernel but in the
> application. Unless your kernel has a bad bug in the UART layer it
> will not withhold data based on control signals.
>
> It is much more likely that the hardware is not configured correctly.

agree

> > >> It seems whatever you have on that port is not asserting DTR,
> > >> which is also odd.
>
> Please comment on this. What do you have connected to the serial
> port? 

I'm trying to get serial console on it -- I connect to alix from my desktop 
with null modem cable 

> Does DTR on the Geode go high when your terminal software is 
> running?

m?

> > > I've asked Pascal Dornier (pcengines) how he sets up uart in his
> > > bios but didn't receive an answer yet.
>
> Please don't ever bother Pascal Dornier with coreboot issues. That is
> what this mailing list and the #coreboot IRC channel is meant for.

I just asked how he sets up uart in his tinyBIOS, that's it. I think this is 
normal question to hw manufacturer.

> > > I still think the problem is in coreboot (or libpayload)...
> >
> > Pascal answered me:
> >
> > After init -> changes to Linux driver, or does it still use Int 10
> > + Int 16 ?
> > My BIOS does a redirect of these BIOS interrupts to the serial
> > console.
>
> You can safely assume that no Linux kernel driver requires real mode
> interrupts. This is an almost universal truth.
>
> In particular: no, the Linux serial driver does not use BIOS
> interrupt services.

maybe coreboot could try to use similar behavior? just to see what it gives?


Roman




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