Messages in this thread | | | Date | Fri, 28 Jul 2023 22:10:36 +0200 | From | Ondřej Jirman <> | Subject | Re: [PATCH] arm64: dts: rockchip: Change serial baud rate for Pinephone Pro to 1.5 MB |
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Hi Heiko and Javier,
On Fri, Jul 28, 2023 at 08:59:50PM +0200, Heiko Stuebner wrote: > > Hi Javier, > > > Probably won't replace the DTB shipped with the firmware either? If one is > > replacing the firmware provided DTB witch the one in the mainline kernel, > > probably such person is also using mainline u-boot? > > Not necessarily. > > I.e. putting an extlinux.conf on an sd-card with a kernel-image and dtb > is not rocket science ;-) > > > For someone like me who is only using mainline u-boot, linux, etc then > > having a consistent uart baud rate across all components is really useful. > > > > Otherwise I either have serial console for u-boot or the kernel, but can't > > have both working so is annoying. > > > > It would be good to have a definite answer on this. Since every time that > > I try to hack on my PPP, I end changing my DTS and remember this patch :) > > So far people only reported "breaks my setup". I'm in a pickle here ;-) . > Without anybody saying "I want to also move into this direction" I really > feel I should not merge a patch that breaks other peoples setups.
Even if this is not changed in kernel, bootloader should fix this situation by patching the kernel DTB before booting the kernel. U-Boot already patches the DTB in several ways, so I guess it's possible to just change stdout-path either in generic code, or in per-board ft_board_setup() for Pinephone Pro to something that matches whatever the user configured via Kconfig:
https://elixir.bootlin.com/u-boot/latest/source/configs/pinephone-pro-rk3399_defconfig#L79
I mean that if U-Boot allows the user to configure arbitrary baudrate via KConfig, then it *should* also update the kernel DTB to match, especially if the choice is different from DTB that it actually embeds:
https://elixir.bootlin.com/u-boot/latest/source/arch/arm/dts/rk3399-pinephone-pro.dts#L29
No static baudrate choice in DT will save anyone anyway, with the provided flexibility of configuration.
Maybe this would be a nice location to fix this:
https://elixir.bootlin.com/u-boot/v2023.07.02/source/common/fdt_support.c#L131
kind regards, o.
> > Heiko > >
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