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

[Wander Costa]

On Mon, Nov 1, 2021 at 12:33 PM Andy Shevchenko
<andy.shevchenko@xxxxxxxxx> wrote:
>
> On Mon, Nov 1, 2021 at 5:22 PM Wander Costa <wcosta@xxxxxxxxxx> wrote:
> > Em sáb., 30 de out. de 2021 04:41, Andy Shevchenko
> > <andy.shevchenko@xxxxxxxxx> escreveu:
> > > On Friday, October 29, 2021, <wander@xxxxxxxxxx> wrote:
>
> ...
>
> > > 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!
>
> ...
>
> > > 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...
> >
> > > 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
>