> If you are lucky, you only need to add 20~30 lines to your chipset's code.
Could you, please, show us an explicit example (of these 20 to 30 lines of code)?! Zoran On Mon, Jun 5, 2017 at 7:34 PM, Nico Huber <nic...@gmx.de> wrote: > Hi, > > On 05.06.2017 18:58, Himanshu Chauhan wrote: > > > >> On 05-Jun-2017, at 10:19 PM, ron minnich <rminn...@gmail.com> wrote: > >> > >> The reason I ask about what you need is that on chromebooks the main > >> coreboot support came down to 'don't disable anything’. > > > > I think its can’t just be disabled. Its just that kernel is not given > > any knowledge about its existence. This is what I want to know. The > > commercial BIOSes give an option of “enable VT-d” support. What do they > > do when this option is selected? Can this be implemented in Coreboot? > > This probably brings me to your next question of what is required. I > > would spend some time to figure that out. > > First thing, the firmware doesn't have to support it. It's only that > Intel chose _not_ to write per platform OS drivers and let the firm- > ware do the abstraction instead (I know a kernel that works pretty well > with VT-d even if there are no DMAR tables). > > coreboot already handles VT-d support on some chipsets (GM45, Sandy/ > Ivy Bridge come to mind). You can look how it's done there. If you are > lucky, you only need to add 20~30 lines to your chipset's code. > > If your chipset needs special initialization, it's most probably docu- > mented in the BIOS Writer's Guide (BWG) or BIOS Specification. Though, > you need an NDA with Intel to get these. > > Nico >
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