What does "supports DRM functions and may not be fully accessible" mean for SATA SDDs?

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2025-01-20 06:30:05

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These messages seem to be new. I cannot remember to have seen them previously. But I don't know since which kernel version they have started to appear.

There's an extension of the ATA protocol (the "language" spoken between your mainboard and your SATA SSDs), which allows for the storage device to reply differently, depending on whether a request was signed by the trusted platform module on the mainboard. That way, things like video player devices that only give access to the stored data when the software has proven itself to be unmodied can be implemented. (I can find much more interesting use cases, but digital rights management seems to be what the kernel authors saw as the application for this when they implemented that warning.) That also means that Linux might simply get an "incomplete" view of the SSD, hence it warns you about that, in case you wonder.

uff, this just tells you that the device has a read cache: the computer fetches some smaller unit of data, and the device keeps that (and potentially more of its surroundings) around in a smaller, faster "transparent" piece of memory. That makes sense, because it's more common that data that was recently read is read again than some data that nobody cared about for a long tim.