[PATCH 13/19] thunderbolt: Add QUIRK_NO_DMA_PORT
Sven Peter
sven at kernel.org
Tue Sep 1 10:06:46 PDT 2026
On 9/1/26 11:04, Mika Westerberg wrote:
> Hi,
>
> On Sun, Aug 30, 2026 at 10:19:31PM +0200, Sven Peter wrote:
>> Apple Silicon machines load and update the host router firmware with a
>> separate, proprietary mechanism and have no DMA port. Add a quirk to
>> skip its initialization.
> DMA port is Intel Thunderbolt 1-3 thing and not expected to found on USB4
> routers. The current code should not even be trying to find it, if it does
> then that's a bug that should be fixed.
>
> USB4 router firmware upgrades use the standard operations and if those are
> not supported then we just don't expose the corresponding NVMem nodes.
Yeah, you're right, I can just drop this and everything still works.
I think this may have been broken back in 2023 when I brought this all
up for the first time (and still had trouble with the Type-C PHY and PD
controller which is why I didn't try to upstream any of this back then)
Sven
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