Linux 6.3 Adds Thunderbolt/USB4 DisplayPort Bandwidth Allocation Mode

Written by Michael Larabel in Hardware on 1 March 2023 at 02:30 PM EST. 1 Comment
Earlier this week Greg Kroah-Hartman submitted the USB/Thunderbolt subsystem updates for the ongoing Linux 6.3 kernel merge window.

Besides the usual churn in the USB gadget driver space and random other device driver additions, most notable with this pull request is implementing DisplayPort Bandwidth Allocation Mode.

Linux 6.3's Thunderbolt driver is implementing support for an optional USB4 feature called DisplayPort Bandwidth Allocation Mode. The DisplayPort Bandwidth Allocation Mode allows the GPU driver to negotiate with the Thunderbolt driver the bandwidth requirements dynamically through DP IN adapters of the host router. As described in the Thunderbolt driver patches, this allows for "fine grained" bandwidth allocation controls for displays connected via USB4/Thunderbolt.

The USB4 bandwidth management allocation mode appears to align with this 2020 patent by Intel.


Linux 6.3 also enables USB support in the mainlne kernel for the Tegra234 SoC, which is the NVIDIA Jetson AGX Orin.

More details on the USB/Thunderbolt changes for Linux 6.3 via this pull.
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