Re: [PATCH v2 1/4] serial: 8250_dw: Keep the BUSY-safe divisor hook when DLF is present

[Vinicius Pedrosa]

Hi Andy,

On Wed, 21 Oct 2026, Andy Shevchenko wrote:

> Yes. but is it only a single device/platform affected or a big class of the
> devices? I assume only narrow part of them which unfortunately use DFL register
> offset for something else in their RTL.

The A733 is the only case I've seen, and the false DLF is what exposed
it. But I don't think the BUSY problem depends on the DLF offset being
reused: with a real DLF on a UART that isn't 16550-compatible,
dw8250_setup_port() also replaces the BUSY-safe setter with the dwlib
one, so the same path exists. I haven't confirmed that on hardware.

With patch 2 the A733 no longer takes that path.

> It all depends on the outcome of the above discussion. Maybe others can share
> their opinions, but I lean towards a series-as-a-fix rather than a bit ugly fix
> + proper refactoring on top.

I'm fine with a series-as-a-fix, and with deferring the deduplication
patch.

Thanks,
Vinicius