Re: [PATCH v1 4/4] usb: serial: mxuport: add sysfs control for UART FIFO

[Crescent Hsieh]

On Thu, May 07, 2026 at 05:59:05PM +0200, Johan Hovold wrote:
> On Tue, Mar 24, 2026 at 11:50:41AM +0800, Crescent Hsieh wrote:
> > Add a per-port sysfs attribute, uart_fifo, to allow userspace to enable
> > or disable the UART FIFO at runtime.
> 
> Why would you want to do that?
> 
> We should try to avoid driver specific sysfs knobs.

The motivation is to allow userspace to choose between lower latency and
higher throughput at runtime. Some latency-sensitive request/response
deployments become unreliable if the UART FIFO is enabled due to the
added buffering delay.

I understand the concern about driver-specific sysfs knobs. UART FIFO
enable/disable seems more like a common UART capability than a
device-unique behaviour.

If a driver-specific sysfs attribute is not the right approach here, do
you have a suggestion for a better interface?

---
Sincerely,
Crescent Hsieh