[coreboot] SeaBIOS, serial output, grub, sgabios does not seem to load

Kuzmichev Viktor kuzmichevviktorv at gmail.com
Tue Jan 20 09:04:42 CET 2015


So, after editing sgabios.h I saw that sgabios actually loaded. As I did 
not disable serial output in SeaBIOS and Grub, I got duplicate 
characters and lines. I know, if I disable all serial output, that 
should most probably solve it. However, I still need debug messages, so 
I decided to use only serial input/output. The only issue with this that 
I had before is that Grub was configured to load splashimage which, it 
seems, interfered with the serial output. So, when I disabled it, it 
loaded just fine.
And now I have the following setup controlled completely by serial 
input/output: coreboot -> SeaBIOS -> Grub -> Linux. There is just one 
little annoying issue now. SeaBIOS does not respond to F12 via serial IO.


On 13.01.2015 06:33, Martin Roth wrote:
> Hi Viktor,
>   Yes, I think having option roms checked is probably required. The 
> only other thing I'd recommend is to build SeaBIOS outside of the 
> coreboot structure and pull it in as an elf payload.  Building within 
> coreboot is handy, but it doesn't offer the flexibility or control 
> that you get building it yourself.
> Martin
> On 01/12/2015 01:50 AM, Kuzmichev Viktor wrote:
>> On 11.01.2015 07:45, Martin Roth wrote:
>>> On 01/10/2015 07:53 AM, Kevin O'Connor wrote:
>>>> On Thu, Dec 25, 2014 at 11:45:40AM +0300, Kuzmichev Viktor wrote:
>>>>> Hello,
>>>>> I've been trying to boot grub installed on the hard drive using 
>>>>> coreboot and
>>>>> SeaBIOS as a payload. The motherboard I'm using is Intel Mohon 
>>>>> Peak. Also, I
>>>>> do not use VGA for output, only serial port. So, I included the 
>>>>> sgabios into
>>>>> my rom file. Here is its layout:
>>>> It should have worked.  How did you build SeaBIOS, what SeaBIOS config
>>>> did you use, and what changes have you made to SeaBIOS?
>>>> -Kevin
>>> As I recall, Mohon Peak uses 0x2f8 for the console serial port. Did 
>>> you set sgabios to output to 2f8 instead of 3f8 in sgabios.h?
>>> sgabios.h:#define COM_BASE_ADDR           0x3f8
>>> Martin
>> Thank you for your replies!
>> Just checked sgabios.h and changed serial port base address to 2f8. 
>> Somehow I missed it earlier, although I did set this parameter in 
>> both coreboot and SeaBIOS before. Sadly, I do not currently have 
>> access to Mohon Peak, so I can't really test this right now but, 
>> hopefully, I would be able to test this in a few days.
>> Also, I'd like to clarify one more thing. Should Option ROMS 
>> parameter in SeaBIOS menuconfig be checked for sgabios to work? Are 
>> there any other nuances I should keep in mind?
>> Viktor

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