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.
It’s literally got WIFI printed on the board below it, likely a slot for a wifi card.
…a wifi card that uses a certain type of M.2 connector
Sure, but there are several and op didn’t specify what they wanted to do with it, typically if someone uses the m2.22xx naming they expect to put storage in it, which would not work here. So I was just trying to make that especially clear.
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.
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.
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.
But this one looks like SATA
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?)
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.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
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
SATJA slot
IℲIM slot
There are adapters that allow you to plug an M-key SSD into that A+E-key slot, for example that one: https://www.delock.de/produkt/64137/merkmale.html?f=s
They should work on most computers, but some machines have a whitelist of supported WiFi cards and ignore anything else you plug into the slot for the WiFi module.