anishp55: you may be running into a resolution issue between the VBIOS and AMIBIOS8.
Not all of the resolutions supported at the OS level work in BIOS. This is somewhat of a VBIOS issue, but it also is based on the VGA standard (built on 80x25 text modes and 4:3 aspect displays).
So a 480x640 panel may not work but a 640x480 panel will probably work.
For the 1024x600 panel ... my guess is that the VBIOS during BIOS boot is actually running at 800x600 resolution and the VGA is expanding that to fill the 1024x600 screen (does our "red triangle" logo look more obtuse than isosceles?). Then the OS driver sets the actual resolution based on the panel type (the OS driver is more flexible and understands different aspect ratios).
anishp55: hard to say, since there are no that many GOP drivers in production right now. The UEFI spec sets 800x600 as the minimum GOP resolution, but different drivers may handle this situation in different ways. Someone with the Intel embedded display driver team might have more insight. Most OS today have no GOP support so this isn't the best solution at the moment.
I just finished reviewing the UEFI 2.3 spec on the area regarding GOP. There is actually no mention of the minimum resolution defined by the protocol. Is it possible you are refering to the FastBoot paper that was published by Intel and AMI? In that they say the resolution for the GOP driver is fixed at 800x600 and the EPOG driver is fixed at 1024x768 to speed up boot times.
I should clarify, because there are a number of limitations on resolution that will vary from platform to platform ...
First of all, you are right that the GOP definition has no defined minimum resolution. The AMI UEFI solution (Aptio) and the Intel EPOG drivers were first developed on the previous standard (UGA = Universal Graphics Adapter) which defined a minimum 800x600 resolution. This was long before netbooks and tablets made 800x480 popular. GOP was developed to fix some problems in the UGA definition.
Right now, Aptio keeps a minimum GOP resolution of 800x600. We have not run into issues with this setup, but the majority of vendors use legacy video BIOS so the full set of UGA features have not been taken advantage of yet.
Video card and OS vendors are going to have different definitions of minimum mode based on hardware and driver implementation. For Intel EPOG, it makes sense that they set a default mode to simplify the driver, but the mode size may have to change given the variety of display sizes on the market.
Once the video display manufacturers determine what modes they want to support in the UEFI GOP drivers, the BIOS vendors can start working on solutions for non-traditional display sizes.
I can produce GOP dxe files from EMGD/IEGD that support my 480x640 resolution, and get get a patched grub to support UGA/GOP. My customer is using linux, and i am pretty sure that mainline has support for GOP @ boot time. Could AMI modify the boot resoltion if a resquest was put in?
Questions?
