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0 pointsconradev7y ago0 comments

Where are they getting the LTE baseband software from?

0 comments

They're not of course. They just treat the modem as walled off peripheral black box like all the other rest of the hardware. They may load firmware on boot for LTE/Wifi/Bluetooth like most Linux laptops do. Depending on your opinion on the topic that may be free enough or not but it should be safe as none of those can access the CPU/RAM directly.

conradevOP7y ago

I see. The question here is not if there will be proprietary software: there will be. The question is which of that proprietary software runs on the CPU.

Is the idea that all of the software in the kernel to interface with these devices is open source?

I also don’t get the hangup over PCIe (vs USB). DMA with an IOMMU can be made fairly secure (and has obvious perf benefits).

pedrocr7y ago

> I see. The question here is not if there will be proprietary software: there will be. The question is which of that proprietary software runs on the CPU.

I'm pretty sure no closed source software runs on the CPU. As for the hardware that depends on your definition. Hardware often has firmware in ROM. That you now feed that firmware on bootup instead of it being in ROM just allows you to update the firmware from the manufacturer. If that's running proprietary software depends on your definition.

cyphar7y ago

I think the main reason is that powering off a device (for their hardware kill switches) connected via USB is more reliable than powering off a device connected via PCIe.

There's also just more layers of security when using USB as opposed to a single layer with PCIe (IOMMU -- which is secure as far as I know but I'd prefer to be safe rather than sorry in this case).

3 more replies

sneak7y ago

Reminds me of a joke I heard:

What’s the difference between a person and a cellphone?

A person only has two arms.

floatboth7y ago

They don't have the baseband on the same chip, the modem is connected over something like USB (and there's probably gonna be a physical kill switch).

IIRC this is fine even under FSF "Respects your Freedom" rules

j / k navigate · click thread line to collapse

0 comments

pedrocr7y ago

conradevOP7y ago

I see. The question here is not if there will be proprietary software: there will be. The question is which of that proprietary software runs on the CPU.

Is the idea that all of the software in the kernel to interface with these devices is open source?

I also don’t get the hangup over PCIe (vs USB). DMA with an IOMMU can be made fairly secure (and has obvious perf benefits).

pedrocr7y ago

> I see. The question here is not if there will be proprietary software: there will be. The question is which of that proprietary software runs on the CPU.

cyphar7y ago

I think the main reason is that powering off a device (for their hardware kill switches) connected via USB is more reliable than powering off a device connected via PCIe.

There's also just more layers of security when using USB as opposed to a single layer with PCIe (IOMMU -- which is secure as far as I know but I'd prefer to be safe rather than sorry in this case).

3 more replies

sneak7y ago

Reminds me of a joke I heard:

What’s the difference between a person and a cellphone?

A person only has two arms.

floatboth7y ago

They don't have the baseband on the same chip, the modem is connected over something like USB (and there's probably gonna be a physical kill switch).

IIRC this is fine even under FSF "Respects your Freedom" rules

j / k navigate · click thread line to collapse