Re: [PATCH] tty: serial: Use fifo in 8250 console driver

On Mon, Nov 1, 2021 at 12:33 PM Andy Shevchenko
[off-list ref] wrote:

On Mon, Nov 1, 2021 at 5:22 PM Wander Costa [off-list ref] wrote:

quoted

Em sáb., 30 de out. de 2021 04:41, Andy Shevchenko
[off-list ref] escreveu:

quoted

On Friday, October 29, 2021, [off-list ref] wrote:

...

quoted

quoted

I don't see any links.

Oops, sorry about that. I must have accidentally deleted it while
editing the commit message.
Here it is https://github.com/walac/serial-console-test.
I will update the patch with the link.

Thanks!

...

quoted

quoted

On how many different UARTs have you tested this? Have you tested oops and NMI contexts?

I only tested in a half dozen machines that I have available. I tried
it in panic, warnings, IRQ contexts, etc. Theoretically, this change
should not be affected by the context. Theoretically...

quoted

What I would like to say here is that the code is being used on zillions of different 8250 implementations here and I would be rather skeptical about enabling the feature for everyone.

I did my homework and studied the 16550 datasheets, but yes, there is
always this risk. Maybe people more experienced with PC serial ports
than me might think the patch is not worth the risk of breaking some
unknown number of devices out there, and I am ok with that. It is a
valid point.

Here is a translation of my comment to a roadmap.

1. Introduce yet another UART quirk or capability (see corresponding
UART_CAP_* or UART_*_QUIRK definitions)
2. Add your patch conditionally based on the above
3. Enable it on UART(s) you _have tested_

Thank you for the feedback, I submitted a v2 patch with your proposed changes,

Cheers,
Wander

--
With Best Regards,
Andy Shevchenko