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Re: Multiboot video mode request on EFI-gop


From: Thomas Nilsen
Subject: Re: Multiboot video mode request on EFI-gop
Date: Mon, 16 Jan 2012 16:50:11 +0100

Hi again,

Thanks for you help.

That actually means that Grub2 is actually doing what it can and thats it? The rest is up to the os/kernel to handle directly with the GOP protocol driver?

So its not possible to have the GOP driver initialize a mode and then return a LFB address? The GOP protocol in the machine's EFI bios is most definetly not video-hardware specialized, so between the GOP implementation and the VIDEO hardware there must be some sort of LFB type interface? Or am i misunderstanding?

The ideal solution for me would be if grub could initialize mode as it does very well, then in some way get the LFB pointer and bpp, etc and send as if it was from a Bios+vbe grub scenario.

regards
Thomas

2012/1/16 Phillip Susi <address@hidden>
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Hash: SHA1

On 1/16/2012 10:22 AM, Thomas Nilsen wrote:
> Hi,
>
> I think i might have explained myself incorrect.
>
> What i mean is:
>
> 1. Grub2 runs very well on BIOS & (U)EFI bios. Nice graphics as
> requested in gfxmode etc.
>
> 2. Grub2 loads multiboot kernel and gives it its requested
> videomode (from the videomode request part of multibootheader)
>
> 3. Grub2 does NOT load multiboot kernel and gives it its requested
> videomode. It seems to give it its mode, but the info is not right
> in the multiboot parameters.. So the "kernel" cannot tell what mode
> it is, where its LFB is and bpp etc.

Ahh, yes, this is because gop doesn't set a vesa mode and let you play
with the flat frame buffer.  You actually  make gop calls to perform
the IO for you.  Grub can leave the display in that state when passing
off to the kernel, but the kernel has to have its own KMS video driver
to take over; it can't just start poking at a frame buffer like it can
with VESA.

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