Re: Display Architecture and Bring Up in UEFI

[prabin ca <prabinca4u@gmail.com>]

Thanks Ruiyu, for confirming.

> On 27-Nov-2018, at 7:15 AM, Ni, Ruiyu <ruiyu.ni@Intel.com> wrote:
> 
>> On 11/23/2018 5:19 PM, Laszlo Ersek wrote:
>>> On 11/23/18 07:27, prabin ca wrote:
>>> Hi Team,
>>> 
>>> I’m new to UEFI and display interface in UEFI. I would like to have deep dive into how display is working in UEFI (display architecture) and how display is have been bring up (porting of display panel in a any platform in general ).
>>> 
>>> Please help me with sample codes and necessary documents. I would like to get knowledge about display bring up and display architecture in UEFI
>> The driver writers' guide and the UEFI spec have relevant chapters on
>> this. I think it's best to start reading the former, at "23 Graphics
>> Driver Design Guidelines"; that part will give you the pointers to the
>> rest as well.
>> https://github.com/tianocore/tianocore.github.io/wiki/UEFI-Driver-Writer%27s-Guide
>> For a (hopefully educational) example, I refer you to
>> OvmfPkg/VirtioGpuDxe. In the series that first added this driver to
>> edk2, I managed to construct the driver in stages such that each stage
>> would build and even function, at the level expected from that stage. In
>> particular, commit a2a4fa66701d ("OvmfPkg/VirtioGpuDxe: introduce with
>> Component Name 2 and Driver Binding", 2016-09-01) could prove helpful,
>> as it adds the skeleton of the driver, mostly without VirtIo GPU specifics.
>> In addition, you might want to look into the generic
>>   MdeModulePkg/Universal/Console/GraphicsOutputDxe
>> driver. A platform may be able to incorporate that driver without any
>> changes, and control it by first producing the two HOBs in the PEI phase
>> that the driver consumes:
>>   MdePkg/Include/Guid/GraphicsInfoHob.h
>> (... Interestingly, due to the fact that this header file is under
>> MdePkg and not MdeModulePkg, I've just learned, from the related commit
>> messages, that the PEI phase has standardized graphics support,
>> described in the PI spec. From the following two commit messages:
>> - 697c6cf32693 ("MdePkg: Add PI 1.4 Graphics HOB and PPI header files",
>> 2015-04-28)
>> - 2af538fbf667 ("MdeModulePkg: Add GraphicsOutputDxe driver.", 2016-10-12)
>> it appears that enabling graphics support in the PEI phase could be a
>> *requirement* for using GraphicsOutputDxe in the DXE phase. That might
>> or might not match your use case, so perhaps it will prevent you from
>> using GraphicsOutputDxe. I'm not sure.)
> 
> Yes. GraphicsOutputDxe layers on the HOB produced in PEI phase to provide GOP protocol.
> 
> 
>> Thanks
>> Laszlo
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> 
> 
> -- 
> Thanks,
> Ray