Hello Rafael, Chipset initialization should be done in the PEI phase, along with the initialization of any critical hardware (DRAM, etc.). In DXE, usually the optional devices are initialized (controllers like USB and such). Here is a nice picture of the boot flow from the TianoCore Wiki:
https://raw.githubusercontent.com/tianocore/tianocore.github.io/master/images/PI_Boot_Phases.JPG For further information, you can check out the Intel Firmware Support Package Documentation, as I believe that many vendor implementations use it, its code or at least based their code of the flow described in the Specification. I would suggest that you make your Audio driver an UEFI driver, as DXE drivers should be primarily used to expose everything needed during the Boot Services availability (NVRAM, System Reset, Console devices and such). By the time an UEFI app would run from the disk, audio would be available. For other drivers using audio, they should install a Protocol Notify hook to handle the Audio protocol installation. Apple has an HDA driver in their firmware (used for VoiceOver in their BootPicker and probably OS loader), in case you want to take a look at how others do it. Regards, Marvin. ________________________________________ Von: edk2-devel <edk2-devel-boun...@lists.01.org> im Auftrag von Rafael Machado <rafaelrodrigues.mach...@gmail.com> Gesendet: Montag, 28. März 2016 18:00 An: edk2-devel@lists.01.org Betreff: [edk2] Question about Chipset initialization Hi everyone. I'm doing some studies related to audio at UEFI. To in future enable BIOS to be accessible. This is part of my MSc in Computer Science degree. It's take some time, but I'm not worried. The challenge was already accepted. Currently I'm checking is the chipset is already enabled correctly at the point a UEFI application can be executed after DXE phase. My questions are: What is normally the driver that enable the chipset? Is it at PEI phase or at DXE phase ? To understand the scenario and how things work at this point, I'm doing some reverse engineering using UEFITool and the framework radare2. Any other idea about how to proceed with these studies would be appreciated. Thanks and Regards Rafael R. Machado _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
