Re: [PATCH v5 17/17] serial: 8250: Add 8250_acpi driver

Andy Shevchenko
2024-05-02T10:10:08Z

On Thu, May 02, 2024 at 03:20:08PM +0530, Sunil V L wrote:
> On Thu, May 02, 2024 at 12:17:59PM +0300, Andy Shevchenko wrote:
> > On Wed, May 01, 2024 at 05:47:42PM +0530, Sunil V L wrote:

...

> > > + * This driver is for generic 16550 compatible UART enumerated via ACPI
> > > + * platform bus instead of PNP bus like PNP0501. This is not a full
> >
> > This has to be told in the commit message. Anyway, we don't need a duplication
> > code, please use 8250_pnp.
>
> Thank you for the review!. Major issue with PNP0501 is, it gets enumerated
> in a different way which causes issue to get _DEP to work.
> pnpacpi_init() creates PNP data structures which gets skipped if the
> UART puts _DEP on the GSI provider (interrupt controller). In that case,
> we need to somehow reinitialize such PNP devices after interrupt
> controller gets probed.

Then fix that code, we don't want a hack driver on top of the existing one for
the same.

What I might think out of head is that used IRQ core for your case should
return a deferred probe error code when it's not ready, then 8250_pnp will
get reprobed.

> I tried a solution [1] but it required several
> functions to be moved out of __init.

> This driver is not a duplicate of 8250_pnp. It just relies on UART
> enumerated as platform device instead of using PNP interfaces.
> Isn't it better and simple to have an option to enumerate as platform
> device instead of PNP?

Ah, then extract platform driver first from 8250_core.c.

> [1] - https://patchwork.kernel.org/project/linux-pci/patch/20240415170113.662318-14-sunilvl@ventanamicro.com/

--
With Best Regards,
Andy Shevchenko