linux-kernel - Re: [PATCH] serial: 8250: probe all 16550A variants by default

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Message-ID: <20200525172815.GA445190@localhost>
Date:   Mon, 25 May 2020 10:28:15 -0700
From:   Josh Triplett <josh@...htriplett.org>
To:     Vladimir Oltean <olteanv@...il.com>
Cc:     gregkh@...uxfoundation.org, linux-serial@...r.kernel.org,
        jslaby@...e.com, andriy.shevchenko@...ux.intel.com,
        lukas@...ner.de, heikki.krogerus@...ux.intel.com, vigneshr@...com,
        linux-kernel@...r.kernel.org, fido_max@...ox.ru,
        radu-andrei.bulie@....com
Subject: Re: [PATCH] serial: 8250: probe all 16550A variants by default

On Mon, May 25, 2020 at 04:02:38PM +0300, Vladimir Oltean wrote:
> On NXP T1040, the UART is typically detected as 16550A_FSL64. After said
> patch, it gets detected as plain 16550A and the Linux console is
> completely garbled and missing characters.

Interesting that there's *new* powerpc hardware that needs these
variants. I based the patch on the fact that, on x86 at least, hardware
using these variants hasn't been made for a long time.

In the hopes of preserving at least part of the benefit of the patch,
could you please change it to `default y if !X86_64`?

>  drivers/tty/serial/8250/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
> index af0688156dd0..89c7ecb55619 100644
> --- a/drivers/tty/serial/8250/Kconfig
> +++ b/drivers/tty/serial/8250/Kconfig
> @@ -63,6 +63,7 @@ config SERIAL_8250_PNP
>  config SERIAL_8250_16550A_VARIANTS
>  	bool "Support for variants of the 16550A serial port"
>  	depends on SERIAL_8250
> +	default y
>  	help
>  	  The 8250 driver can probe for many variants of the venerable 16550A
>  	  serial port. Doing so takes additional time at boot.
> -- 
> 2.25.1
>