Re: [PATCH net-next v2] net: nfc: nci: Turn data timeout into a module parameter and increase the default

[Juraj Šarinay]

On Wed, 2025-08-27 at 15:29 +0200, Krzysztof Kozlowski wrote:

> CardOS is the software running on the NFC card, right? 

Yes it is. I may have been too specific, all I am saying is that I made
some measurements.

> If so, why would this be Linux kernel module param? Kernel runtime setup is really
> independent of what NFC card people will use.

I suggested a tunable timeout because I am not sure what the new
universal upper bound should be. It may depend on the NFC card one is
communicating with. I have since learned that module parameters are
strongly discouraged (within netdev at least).

> I think this should be unconditionally raised

I am fine with that, but would argue for an even more generous timeout.
Five seconds, say? One can always set a shorter SO_RCVTIMEO from user
space if needed.

Ideally, the kernel would also honor a longer SO_RCVTIMEO and treat
NCI_DATA_TIMEOUT as a default rather than a rigid limit, completely
obviating my subjective need for a parameter. I have not explored the
idea further, given that a somewhat higher value of NCI_DATA_TIMEOUT
solves most problems.

Best,
Juraj