Matt B <matthewwbradl...@gmail.com>: > > Is there any conceivable reason that the dGPU present would have bearing on > the iGPU voltages? > > Is it possible that this is a mistake, and that the voltage was intended for > the iGPU by the original developer? > Is it possible that the two reflect different revisions, that one is a > corrected version of the other? >
Maybe Lenovo wanted to do that for all the G505S (e.g. to improve the graphics stability) but mistakenly did that only for "G505S dGPU R5" version, which was the latest released? Hard to check, because the UEFI source code is closed, and it would be quite time consuming to extract these blobs for comparison while running the older UEFI versions. We have not observed any negative results with using this "slightly higher voltages" integrated GPU ROM from "G505S dGPU R5 version" for different G505S. > On Wed, Feb 27, 2019 at 9:58 AM Ivan Ivanov <qmaster...@gmail.com> wrote: >> >> Interesting discovery about the AtomBIOS files at " g505s-atombios " >> repository - https://github.com/g505s-opensource-researcher/g505s-atombios >> : >> >> While there was the same "clean" proprietary UEFI image flashed both >> to "G505S with HD 8570M" and to "G505S with R5 M230" before the >> AtomBIOS extraction, their AtomBIOSes for _ integrated HD 8650G _ >> turned out as slightly different! (see sha256) >> >> So I made their full disassembly with this AtomDis tool - >> https://cgit.freedesktop.org/~mhopf/AtomDis/ , and compared, diff >> results here - https://pastebin.com/eewzswnD . As you could see from >> these diff results, for some reason "G505S R5 version" sets a slightly >> higher voltages for its' integrated GPU : >> >> compared to "G505S HD version" it is 1.8% - 3.2% higher if these 0x3e >> / 0x40 / 0x6e / 0x70 values are linear and 0x0 = 0 volts. >> (usNBP0Voltage / usNBP1Voltage / usVoltageID ) >> >> What do you think: would it be okay to use the integrated VGA BIOS >> obtained from "G505S R5 version" for "G505S HD version" ? >> This voltage difference seems small enough and the integrated GPU is >> the same part after all ---> I think that it should be fine. >> _______________________________________________ >> coreboot mailing list -- coreboot@coreboot.org >> To unsubscribe send an email to coreboot-le...@coreboot.org _______________________________________________ coreboot mailing list -- coreboot@coreboot.org To unsubscribe send an email to coreboot-le...@coreboot.org
