UEFI GOP strange behavior

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psdgijdfi
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Joined: Tue Oct 08, 2013 6:19 pm

UEFI GOP strange behavior

Post by psdgijdfi »

Hi.
I'm working on implementing UEFI graphics output protocol.
I read the GOP structure to get framebuffer size. It works on VMware, but when I change the resolution, the framebuffer size remains the same (3145728 = 3MiB).
Also, the framebuffer size reported by virtualbox is strangely big.

What is the problem?

Thanks in advance.
20131214_001_virtualbox_malfunction.png
Last edited by psdgijdfi on Sun Dec 15, 2013 7:58 am, edited 1 time in total.
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Combuster
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Re: UEFI GOP strange behavior

Post by Combuster »

1024x768x4 = 3MB so that's not surprising.

Your base and size printed in the screenshot look like garbage, which means you're probably not getting that information out correctly.
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psdgijdfi
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Re: UEFI GOP strange behavior

Post by psdgijdfi »

Actually, the base address is correct (it is hexadecimal). I checked the address by filling the screen.

It is strange because the base address and the framebuffer size information is in the same structure, but only one of them is correct.

And, I meant this strange situation. Even though I changed the resolution to 1920x1080x32, the buffer size remains the same. :(
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feryno
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Re: UEFI GOP strange behavior

Post by feryno »

Maybe it is related to VMware emulator - only its UEFI firmware.
How does it behave on real hardware?
hypervisor-based solutions developer (Intel, AMD)
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