You see, Nico, you implicitly answered to Ron's quest to make Coreboot vBIOS/GOP WiKi page... :-)
> Maybe this helps you to untangle this: When the VBT was invented, it > might have been named after Intel's Video BIOS because that was its > first consumer. However the name is or has become unrelated to its func tion. > If somebody would come up with a name for the VBT, looking at what > it is today, he might call it *Intel Graphics Driver Configuration Table* > (IGDT). The acronym IGDT looks much different from VBE, no temptation > to see them related. Also, why should GOP replace IGDT and reinvent how > Intel develops its graphics drivers? GOP is just about pre-OS environ- > ments (cross-vendor), while IGDT is common to all of Intel's graphics drivers. Nico/Matt, You two (as a team) are the best candidates to make this Coreboot WiKi page. It will have Thermonuclear Hit/Influence on the Open Net and Open Source. I do agree on name: *Intel Graphics Driver Configuration Table (IGDCT). Instead VBT!* I'll tell to you: INTEL (devil) himself will consider to change VBT name to what you have proposed. :-) Does it sound reasonable?! ;-) Thank you for understanding, Zoran On Wed, Apr 5, 2017 at 7:54 PM, Nico Huber <[email protected]> wrote: > On 05.04.2017 17:03, Zoran Stojsavljevic wrote: > > To Coreboot, > > > > http://www.uefi.org/sites/default/files/resources/ > UPFS11_P4_UEFI_GOP_AMD.pdf > > > > Please, read about GOP, and what GOP suppose to be. > > > > So, GOP actually need to replace vBIOS, VBT, legacy INT 10H, and complete > > VBE 3.0 standard. Why (I have no idea what INTEL does with GOP and how it > > implements it) it is not done in this fashion...?! At least this is my > > impression how this should be done. > > no, no, no, no. Since VBT is not related to the concept of a Video BIOS > or any standard (how many people does it need to convince you? :-), it > cannot be replaced by something (GOP) that continues this standards > story. > > Maybe this helps you to untangle this: When the VBT was invented, it > might have been named after Intel's Video BIOS because that was its > first consumer. However the name is or has become unrelated to its func- > tion. If somebody would come up with a name for the VBT, looking at what > it is today, he might call it Intel Graphics Driver Configuration Table > (IGDT). The acronym IGDT looks much different from VBE, no temptation > to see them related. Also, why should GOP replace IGDT and reinvent how > Intel develops its graphics drivers? GOP is just about pre-OS environ- > ments (cross-vendor), while IGDT is common to all of Intel's graphics > drivers. > > From another perspective: IGDT contains proprietary settings for Intel > silicon, close to register level. VBE is, at its core, about high-level > framebuffer (data in RAM) formats. > > Nico > > > > > I'll continue to investigate. > > > > Thank you, > > Zoran > > > > On Wed, Apr 5, 2017 at 4:54 PM, Matt DeVillier <[email protected] > > > > wrote: > > > >> On Tue, Apr 4, 2017 at 10:12 PM, Zoran Stojsavljevic <zoran. > >> [email protected]> wrote: > >> > >>> Hello Matt, > >>> > >>> Pretty sure there is NO Option ROM, vBIOS and INT10H. Why INTEL for GOP > >>> uses VBT is point of debate. Probably just reduced functionality up to > >>> 1280x1024. So they have VBT to support BIOS phase GOP GFX. Only! > >>> > >> > >> From what I can tell, it's mainly used to provide the output connector > >> types/mapping to the GOP driver, as well as level shifting etc. > >> > >> > >>> > >>> But I am also 100% sure neither GOP, neither VBT survives post BIOS > >>> phase. It is out of mind to use VBT for WUXGA, or 1080p, or 4K > displays, > >>> don't you agree? The detected GFX I/F are passed to Linux as Run Time > info > >>> (via HOB). Then Linux brings from scratch GFX, using its own, modern > I/Fs. > >>> And ports appropriate drivers to existing GFX info from HOB. > >>> > >> > >> The VBT data is used by both the Linux and Windows display drivers (via > >> the OpRegion ACPI structure), and the latter will give you a nice black > >> screen if your VBT is missing or incorrectly configured. As I noted > above, > >> it appears to be used more for output/pipe info than display modes > (which > >> are all generated from EDID, outside of standard VESA/CEA ones) > >> > >> On Tue, Apr 4, 2017 at 10:12 PM, Zoran Stojsavljevic < > >> [email protected]> wrote: > >> > >>> Hello Matt, > >>> > >>> Pretty sure there is NO Option ROM, vBIOS and INT10H. Why INTEL for GOP > >>> uses VBT is point of debate. Probably just reduced functionality up to > >>> 1280x1024. So they have VBT to support BIOS phase GOP GFX. Only! > >>> > >>> But I am also 100% sure neither GOP, neither VBT survives post BIOS > >>> phase. It is out of mind to use VBT for WUXGA, or 1080p, or 4K > displays, > >>> don't you agree? The detected GFX I/F are passed to Linux as Run Time > info > >>> (via HOB). Then Linux brings from scratch GFX, using its own, modern > I/Fs. > >>> And ports appropriate drivers to existing GFX info from HOB. > >>> > >>> Zoran > >>> > >>> On Tue, Apr 4, 2017 at 11:51 PM, Matt DeVillier < > [email protected] > >>>> wrote: > >>> > >>>> > >>>> > >>>> On Tue, Apr 4, 2017 at 2:23 PM, Zoran Stojsavljevic < > >>>> [email protected]> wrote: > >>>> > >>>>> Furthermore, let me tell you all that this is a mechanism to support > >>>>> ONLY The Legacy BIOS (UEFI works ONLY with GOP, but this is another > >>>>> dimension/discussion), and, to all of your knowledge (which I have > no idea > >>>>> how deep it is, I doubt), VBT table survives postmortem BIOS. By > Linux, it > >>>>> will be RELOCATED into much higher (over 1MB) 32bit protected mode > memory > >>>>> (addresses recalculated), and still use INT10H, using vBIOS (Option > ROM, my > >>>>> best guess) down there. > >>>>> > >>>>> > >>>> no, the UEFI GOP driver needs the VBT to actually do anything. Look > at > >>>> any current PC UEFI firmware, or even x86 ChromeOS firmware, and > you'll see > >>>> they all use/contain a VBT still. > >>>> > >>> > >>> > >> > > > > > > > >
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