Re: Completely disable graphics support in grub2 x86_64-efi

[Vladimir 'φ-coder/phcoder' Serbinenko]

On 08/26/2010 12:04 PM, KESHAV P.R. wrote:
> 2010/8/26 Vladimir 'φ-coder/phcoder' Serbinenko <address@hidden>:
>   
>>>  Please include the way mainline handles
>>> the issue, as a fallback option in efigfx, in case no graphics/video
>>> mode is found.
>>>
>>>       
>> I don't understand what happens in your case. According to you
>> "videotest" doesn't work (can you confirm?) and according to code GRUB
>> in neither branch tries to detect any other way of configure graphics on
>> EFI. I have a theory that for some reason Linux uses vga_text normally.
>> It's possible to have this behaviour with patch at the end of this
>> e-mail. But that patch can't be incorporated because there is no way to
>> actualy check the availability of vga_text on EFI and on EFI as a
>> firmware it's usualy not. EFI is pretty loosy firmware and is definitely
>> not what I recommend. I recognize that in some cases you have to use EFI
>> (if your hardware is shipped with it) but in case of DUET, it's
>> specifically searching for trouble.
>>     
> Grub hangs when after trying videotest in the commandline. Recent
> firmwares enable bios video while older firmwares use vga_text.
>
>   
DUET isn't a firmware
> I have attached the tarball of actual video driver VgaMiniPort enabled
> in EDK1 DUET. The other video driver option BiosVideo is not compiling
> in EDK1 DUET. I think grub2 tries for the 2nd video driver to be
> present in the firmware.
>
>   
GRUB doesn't handle the choice of driver by EFI. I would recommend
loading only efi_gop since efi_uga is hacky.
If you supply the qemu image to test I might be interested in finding
out the reason of this.
>> Additionaly DUET is labeled as being for test purposes only and not for
>> regular use.
>>     
> I know it is for test purposes only. I compile DUET (both EDK and
> EDK2) in windows using visual studio. I use DUET to boot windows 7 x64
> in UEFI-GPT mode because I have a GPT partitioned disk in a way hybrid
> mbr cannot be used because I need access to all the partitions in
> windows. Windows does not allow mixing BIOS+GPT
Call Microsoft, and tell them to stop telling the crap about the
impossibility of GPT+BIOS.
>  like linux or grub2
> allows. If you to try the DUET firmwares you can download it from
> http://tiano-efi-duet-folder-sk.4shared.com/ where I have given
> instructions on how to set it up (requires windows).
>
>   
EDK2 can be compiled with mingw under GNU/Linux.
You don't approach the problem from right angle. Rather than trying to
make grub work under DUET with all the incurring penalties you should
look into loading DUET from GRUB. If DUET supported multiboot it would
be trivial. I would recommend suggesting multibootor multiboot2 to DUET
guys. With lack of those you need to stick to chainloader.
> Regards.
>
> Keshav.
>
>   
>> === modified file 'grub-core/loader/i386/linux.c'
>> --- grub-core/loader/i386/linux.c       2010-04-21 17:13:45 +0000
>> +++ grub-core/loader/i386/linux.c       2010-08-26 08:20:20 +0000
>> @@ -638,7 +638,7 @@
>>     }
>>   else
>>     {
>> -#if defined (GRUB_MACHINE_PCBIOS) || defined (GRUB_MACHINE_COREBOOT) ||
>> defined (GRUB_MACHINE_QEMU)
>> +#if 1
>>       params->have_vga = GRUB_VIDEO_LINUX_TYPE_TEXT;
>>       params->video_mode = 0x3;
>>  #else
>>
>>
>>     
>>> Regards.
>>>
>>> Keshav
>>>
>>> _______________________________________________
>>> Grub-devel mailing list
>>> address@hidden
>>> http://lists.gnu.org/mailman/listinfo/grub-devel
>>>
>>>
>>>       
>>
>> --
>> Regards
>> Vladimir 'φ-coder/phcoder' Serbinenko
>>
>>
>>
>> _______________________________________________
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>> address@hidden
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>>
>>
>>     
>>
>>
>> _______________________________________________
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>>     


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko

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