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ASpeed AST2600 BMC Support For DisplayPort Landing In Linux 5.19

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  • #11
    Most of the time, the VGA port does not transmit _any_ signal. So no power consumption, no EMI problems. And to be honest, I'm not sure whether DP and especially HDMI with its rather high-voltage differential transmission do really need more power than VGA. Both are using 75...100 ohm termination, and the voltage is even higher for HDMI than VGA. The power for hsync/vsync is negelectable because ot the very low frequency.

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    • #12
      regarding USB-C: uh, combining rather thick cables for USB + DP lanes and a tiny plug without mechanical fastening calls for brocken plugs or, worse, ports. Specially if there are rail systems for the machines...
      Last edited by mifritscher; 06 May 2022, 06:28 PM.

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      • #13
        Originally posted by mifritscher View Post
        Most of the time, the VGA port does not transmit _any_ signal. So no power consumption, no EMI problems. And to be honest, I'm not sure whether DP and especially HDMI with its rather high-voltage differential transmission do really need more power than VGA. Both are using 75...100 ohm termination, and the voltage is even higher for HDMI than VGA. The power for hsync/vsync is negelectable because ot the very low frequency.
        VGA or Displayport or HDMI off that does basically kill the power draw. No power consumption no EMI problem is correct but this becomes intermitted bug because when someone turns on port to diagnose some other problem you have added problem.

        HDMI is not a totally different voltage. The DCC(the bit to id the montior what is is) on vga runs 5 volts like everything else at 300mA to 1A there is a problem here note the range the HDMI and Displayport has this under 500mA. General VGA to deal with random monitors and cables you will be over 600mA to make sure it works.

        When talking about EMI you are the Amperes are very important. Interesting point is the higher voltage equals less resistance covering power to heat that equals lower Amperes to send the same signal. So lower losses going to the higher voltage.

        Just to be horrible the volts in EMP signal noise measurements is a different value complete to volts you measure with a multimeter on a wire. Yes EMP calculations you end up using more Watts over wire than volts or amperes.

        Yes higher the voltage the less amperes are need to deal with the 70-100ohm termination. Basically going up in voltage end up reducing your over all current travelling along the wire and it the current that is important for how bad the EMI will be.

        I will give you the EMI measurement of volts and the wire measurement of volts in fact being different things lead to the common mistake the higher wire voltage equals higher EMI volts so bigger EMI problem when this is not the case. Yes your ignored that the voltages up for HDMI and display-port but the overall amps other than power supply wires goes down.(yes the lines used to power converters and the like)

        Yes its really simple to forget that the DCC is there with VGA running at 5volts just like Displayport and HDMI and that is also running in most cases at higher amperes this is where your biggest VGA EMI headache comes from and its nicely intermitted so your worse class of issue to be tracing down.

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        • #14
          I wish the DC I worked at had those 1U terminals in the cold aisles. We use crash carts to connect to power and VGA in the hot asiles. Seeing how expensive they are I understand why we don't have one for each rack! Wish we did though, or IMPI for all servers but nope we don't even have that.

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          • #15
            The DCC(the bit to id the montior what is is) on vga runs 5 volts like everything else at 300mA to 1A
            Eh, no. At first, also HDMI and DVI have dedicated DDC pins as well - with exactly the same functionality and protocol. Secondly, DCC is no bit, but a I2C bus, which uses a few mA. In fact, the pull ups often are in range 1-10 kOhms, which means about 0,5...5 mA.

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            • #16
              Originally posted by uid313 View Post
              So does the ASpeed AST2600 contain a GPU?
              Is it licensed IP or an in-house developed GPU?
              Is it compatible with OpenGL? Like even OpenGL 1.1?
              ASPEED "GPUs" are a pile of feces. I promise that you've never used such garbage as these.

              AST2600 is ASPEED's 7th generation Server Management Processor, and also the world's first BMC SoC adopting 28nm advanced process technology.


              That's right - they use the same ARM core as 1st gen Raspberry Pi. Except, now there's 2 of them! And they use the 28 nm manufacturing process that was cutting-edge about 10 years ago.

              As such, it wouldn't make sense to do any 3D acceleration on them, since running llvmpipe or lavapipe on your host CPU would perform vastly better.

              The only good thing I can say about them is that you can use them to remotely upgrade a machine's BIOS, when the host processor can't even boot (e.g. because you're using a newer CPU than the motherboard originally supported).

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              • #17
                Originally posted by Rob72 View Post
                Most new monitors no longer even offer VGA.
                Gaming monitors don't, but more "productivity"-oriented monitors often still have a DVI-I port.

                Failing that, you can use a VGA -> HDMI converter. I see one on Amazon for $12.

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                • #18
                  Originally posted by mazumoto View Post
                  I'd really like to get BMC functionality and a tiny Radeon GPU - preferably in the same chip - that is enough for simple desktop usage and doesn't require much power. But I don't think there is such a thing.
                  The X570-D4U boards support Ryzen APUs. Of course, I'm not sure to what extent that limits BMC functionality, but it means you actually have usable graphics capability on such machines.

                  Now, if only AMD would sell Ryzen Pro APUs on the open market, because they prevent you from using ECC memory on the non-Pro version.

                  Interestingly, Intel just unlocked ECC support on all Alder Lake CPUs, however you still have to use it with a server/workstation motherboard chipset.

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                  • #19
                    IMHO...VGA on servers has always been a "so what" feature that was only useful when I had no access to the server via SSH or an IPMI console session. Rack mounted, slide-out keyboard-VGA units were always handy, but so was the crash cart with a monitor, keyboard, mouse & tools if needed.

                    As for all the screamers out there, you know the type..."Gotta have mega-sized CPU that consumes multiple kW of power while generating mega BTU of heat along with gobs of RAM and bazillion bytes of storage all crammed into a 1U form factor".

                    Those sorts of demands drive the purchases of hardware that are slightly quieter than a super max jumbo jet at full throttle takeoff power making hearing protection a mandatory item to enter the server room.

                    Yeah, we all want to look like Dumbo the Elephant when we need to go back there to physically toggle a switch. What's next? PPE clothing, eye goggles, & hard-toe shoes?

                    At a certain point a reasonable person just shakes their head and mutters "WTF?!"

                    Simply stated, VGA is simple. It works. Chipsets are dirt cheap and sometimes embedded in other chips. Just about every OS created can dump output to VGA without special drivers. And who needs a GUI interface on a server? A Windows or Apple Admin. Real Admins know how to use SSH and CLI...even us "white beards".

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                    • #20
                      I don't think displayport, in a server, is something that we will use.
                      But for me.. its ok that they add it.

                      AST2600 its a dual core cortex a7,
                      With a micro-controller cortex-m3, and has the capability to support 2GB RAM. It also has a 2d graphics card on chip.
                      For its purposes, its more than adequate, it has plenty of power.

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