Re: [PATCH] arm64: dts: rockchip: Change serial baud rate for Pinephone Pro to 1.5 MB

Javier Martinez Canillas
2023-04-04T08:13:49Z

Heiko Stübner <heiko@sntech.de> writes:

Hello Heiko,

Thanks for your feedback.

> Hi,
>
> Am Montag, 3. April 2023, 19:59:37 CEST schrieb Javier Martinez Canillas:
>> This baud rate is set for the device by mainline u-boot and is also what
>> is set in the Pinebook Pro Device Tree, which is a device similar to the
>> PinePhone Pro but with a different form factor.
>>
>> Otherwise, the baud rate of the firmware and Linux don't match by default
>> and a 'console=ttyS2,1500000n8' kernel command line parameter is required
>> to have proper output for both.
>
> The interesting question is always if this will break someone else's setup.

Indeed.

> I've never really understood the strange setting of 1.5MBps, but on the
> other hand it _is_ a reality on most boards.
>

As far as I understand, it is just to get a faster data transmission but I
have my doubts that it is worth to divert from the more common 115200 rate
just for this.

As you said though, it is a reality and also what mainline u-boot uses for
this device.

> Personally I don't care that much either way, but would like a comment
> from the other people working on that device - if possible.
>

Same, I don't care either but just that would be good to make Linux and
u-boot to match. If this change will break other people setups, maybe I
can convince u-boot to sync with Linux and also use 115200 for the phone.

> I guess if we don't hear anything, I'll apply it nevertheless at some point
>
>
> Heiko
>

--
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat