Re: [PATCH v3] thunderbolt: Stop waiting on a path pending bit that never clears

[Mika Westerberg <mika.westerberg@linux.intel.com>]

Hi,

On Wed, Aug 12, 2026 at 11:42:09AM +0000, Fan Ye via B4 Relay wrote:
> From: Fan Ye <fy15309206903@gmail.com>
> 
> __tb_path_deactivate_hop() waits up to 500 ms for a hop's pending bit to
> read back clear. On an ASMedia ASM4242 host router the host interface
> adapter latches it once enough frames have gone through the DMA ring and
> never clears it again: the teardown finds it already set, seconds after
> the last frame and with the path still up. USB4 v2 table 8-23 has the
> field read only and zero unless packets belonging to the path are waiting
> to be dequeued, so the wait is right and this adapter is not.
> 
> Make the wait a per-adapter length and quirk those routers to zero, which
> leaves the loop reading the bit exactly once. A hop that does drain still
> says so on that read, and one that does not answers -ETIMEDOUT without
> burning the timeout: bringing the interface down takes 6 ms where it took
> 506.
> 
> Assisted-by: Claude:claude-opus-5
> Signed-off-by: Fan Ye <fy15309206903@gmail.com>

I moved the constant to switch.c as I don't think it needs to be exposed
outside. Please check that it still works.

Applied to thunderbolt.git/next, thanks!