Restricted DMA

Posted Jan 8, 2021 11:42 UTC (Fri) by mjg59 (subscriber, #23239)
In reply to: Restricted DMA by flussence
Parent article: Restricted DMA

USB3 doesn't support device-initiated DMA to arbitrary addresses. Are you thinking of Thunderbolt? If so, Gnome and KDE both handle device authorisation out of the box afaik.

Restricted DMA

Posted Jan 8, 2021 13:34 UTC (Fri) by foom (subscriber, #14868) [Link] (1 responses)

Now also known as "USB4".

Restricted DMA

Posted Jan 14, 2021 5:20 UTC (Thu) by marcH (subscriber, #57642) [Link]

> [Thunderbolt] Now also known as "USB4".

No, there is absolutely _nothing_ simple in that area.

USB4 re-uses the low layers of Thunderbolt but the Thunderbolt protocol is optional in USB4.

Meaningless "USB-C" and tunneling were not confusing enough, so they decided to double down.

The only way to make this clearer would have been to name the different layers independently as in networking (no one confuses HTTP with Ethernet) because they _are_ independent now. Too late.

Restricted DMA

Posted Jan 9, 2021 19:18 UTC (Sat) by flussence (guest, #85566) [Link]

>Are you thinking of Thunderbolt?

Probably, yes. I haven't been able to keep up with The One True Universal Connectivity Standard since they added half a dozen new ones to the same port.

Though this sounds like it'd be a good thing for Firewire too, if anyone still cared about it? I seem to remember plug-and-play DMA access being a “feature” back in the day…