• drathvedro@lemm.ee
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    6 months ago

    Maybe you’re right, but I haven’t seen a GPU that doesn’t have at least 4 distinct outputs in a while, not that I’d expect one in a machine of this class either. The problem, if I were to guess, is that this machine has AMD iGPU with Nvidia dGPU and a switchable MUX on top of that so it could boot with(or without) either as primary. That’s like three points of failure already. On top of that, I had the main panel cracked and badly malfunctioning, so I’ve removed it, just in case, for about a month while I waited for replacement. I guess some firmware update did not expect the main panel to be missing(or to have different s/n) during update and did something stupid to the mux setting that made it so that two outputs can’t be active simultaneously. I’ve tried to reach someone half-competent at ASUS for like a couple months, then just said “fuck it” and installed linux. Now living happily with 6 displays up and running, theoretically up to 9 if I do some output splitting shenanigans. Someday I’ll actually build that setup just to dunk on that rep who told me it could only handle 3.

    • areyouevenreal@lemm.ee
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      6 months ago

      It’s fairly common for iGPUs to have less outputs. Apple M1 was especially bad as it only had 2, and the internal screen on the laptops couldn’t even be disabled if I remember correctly. I think many Intel (or maybe AMD) iGPUs only have three outputs.

      Yeah it definitely sounds like a driver issue. I have had issues with dual GPU systems like that on Linux, not had any on Windows yet. It would be interesting to see to be honest. I’ve had laptops before where the video ports would only connect to the dGPU, and the internal screen used Optimus (display output from the iGPU with graphics acceleration from the dGPU on demand). Lots of dual GPU laptops are MUXless like that in fact.

      • drathvedro@lemm.ee
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        5 months ago

        It would be interesting to see to be honest

        I still have the video I’ve sent to them at some point, it describes it in all detail, if you can bear my accent..

        I’ve had laptops before where the video ports would only connect to the dGPU, and the internal screen used Optimus (display output from the iGPU with graphics acceleration from the dGPU on demand). Lots of dual GPU laptops are MUXless like that in fact.

        Yeah, I’ve had some of those. Actually owned one of the first generation optimus laptops and it was horrible, most of the time it did not pick up the heavy load and stayed on iGPU even when playing games. Seems to be much improved a lot in win10-11, but I still prefer the kill-switch.

        This one kind of works like that too, though. The MUX only controls which GPU the main panel is connected to (and with it, the framebuffer). The modes basically are:

        • “Eco” where only iGPU is enabled
        • “Hybrid” where iGPU is main and maintains framebuffer while offloading work to dGPU when needed just as you’ve described
        • “Ultimate” with Nvidia as main, which apparently gives much better framerate and latency because it does not require overhead of workload offloading and framebuffer shuffling, but the dGPU is by far the most power hungry device at 150W TDP which drains the battery in mere minutes, even on idle

        I have had issues with dual GPU systems like that on Linux

        I feel you. My previous setup was a desktop with both AMD and Nvidia cards, which I juggled between the host and VM. It was pain, mostly because Nvidia did not want to play nicely. Also because most utilities assumed I had Intel APU — I didn’t, but it was fair assumption at a time. Nowadays, it seems like everything’s sorted out, even VFIO was a breeze to set up (though what for, most games now play on linux nowadays thanks to steamdeck)