• dudeami0@lemmy.dudeami.win
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    1 month ago

    It’s is M.2, but not the M/B+M key most M2 SSDs use but rather a A+E meant for WIFI/Bluetooth. According to this video it’s essentially 2 PCI Express x1 lanes and USB 2.0. The video goes on to explain some possible alternative uses:

    • A gigabit ethernet adapter
    • 2x SATA ports for a standard SATA drive
    • Coral tensor processor
    • SD card reader
    • 2x USB A-type ports
    • Some type of SIM card adapter (video wasn’t quite sure on it either)
    • A PCI Express x16 slot that only functionally works as a x1

    So while does this slot has it’s uses, it’s not meant to be used for M.2 drives but rather WIFI.

    • qupada@fedia.io
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      1 month ago

      it’s essentially 2 PCI Express x1 lanes and USB 2.0

      Sometimes there’s only a single PCIe lane though. And as you say, that’s not a x2 but explicitly two x1s.

      No WiFi card needs the bandwidth (yet), at PCIe 3 speeds you’ve got around 7.8Gbps for a x1, and PCIe 4 double that.

      The Coral comes in a “dual” version for exactly this reason (https://coral.ai/products/m2-accelerator-dual-edgetpu/) you just have to be very sure the slot you’re putting it in is actually delivering two PCIe connections.

      Also for bonus fun, most WiFi/BT cards use the PCIe interface for the WiFi and USB for the Bluetooth.

  • henfredemars@infosec.pub
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    1 month ago

    Looks like one to me. Remember that M.2 is a form factor. You can have an M.2 slot that does not support SSD storage for example. I have one that is only intended to work with wifi adapters.

    Based on the wifi designation on the board I’ll bet it only works with wifi cards.

    M.2 is a form-factor. It talks about the shape only, it says nothing about what the device you are using can do. Many boards have restrictions on supported devices for the physical slot.

      • billwashere@lemmy.world
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        1 month ago

        Yeah I think this an mSATA port.

        Edit: on second glance I think the right part of the connector has too many pins.

    • lukstru@lemmy.worldOP
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      1 month ago

      Oh thanks, I didn’t know that. I thought it was an all purpose PCIe connector. Is there any way to find out whether it supports SSD storage? Is that way the dmidecode from my other comment (and basically saying that it doesn’t support storage?)

      • henfredemars@infosec.pub
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        1 month ago

        The most reliable way I know is to seek documentation for the board. It’s up there with PCI lanes in that the board designer will know what has been configured to work with that physical connector. This kind of info is definitely part of your motherboard documentation.

        I’m not familiar with dmidecode so unfortunately I cannot comment on that.

      • Romkslrqusz@lemm.ee
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        1 month ago

        Is there any way to find out whether it supports SSD storage?

        Have a look at the notch in the slot. SSDs will have either M key, B+M key, or very rarely just B key.

        WiFi modules are A, E, or A+E

      • Creat@discuss.tchncs.de
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        1 month ago

        Scroll down a bit in this article. There’s a list of what each of the available keys are required to provide. A “key” in this context is basically a notch in a certain location, which then defines the meaning of the various pins of the connector. Some devices have multiple keys, as some of the specifications have a common subset. Like key A+E is common, because E provides almost everything that A does, so a device that only requires the common interfaces can work in both. Cars that rely on one of the exclusive interfaces will have the specific key of course. This A+E communication is often used for WiFi cards.

        Sockets always only have one key though, for obvious reasons.

        Edit: correction/clarification

  • lukstru@lemmy.worldOP
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    1 month ago

    It looks like it is one, but dmidecode doesn’t show it.

    # sudo dmidecode --type slot           
    # dmidecode 3.4
    Getting SMBIOS data from sysfs.
    SMBIOS 3.0.0 present.
    
    Handle 0x001C, DMI type 9, 17 bytes
    System Slot Information
            Designation: J6B2
            Type: x16 PCI Express
            Current Usage: Available
            Length: Long
            ID: 1
            Characteristics:
                    3.3 V is provided
                    Opening is shared
                    PME signal is supported
            Bus Address: 0000:ff:10.0
    
    Handle 0x001D, DMI type 9, 17 bytes
    System Slot Information
            Designation: J6B1
            Type: x1 PCI Express
            Current Usage: Available
            Length: Short
            ID: 2
            Characteristics:
                    3.3 V is provided
                    Opening is shared
                    PME signal is supported
            Bus Address: 0000:ff:1c.4
    
    Handle 0x001E, DMI type 9, 17 bytes
    System Slot Information
            Designation: J6D1
            Type: x4 PCI Express
            Current Usage: Available
            Length: Long
            ID: 3
            Characteristics:
                    3.3 V is provided
                    Opening is shared
                    PME signal is supported
            Bus Address: 0000:ff:1d.0
    
    Handle 0x001F, DMI type 9, 17 bytes
    System Slot Information
            Designation: J7B1
            Type: x1 PCI Express
            Current Usage: Available
            Length: Short
            ID: 4
            Characteristics:
                    3.3 V is provided
                    Opening is shared
                    PME signal is supported
            Bus Address: 0000:ff:1c.5
    
    
    Wrong DMI structures length: 3135 bytes announced, structures occupy 3136 bytes.