Messages in this thread | | | Date | Fri, 18 Nov 2022 15:08:23 -0600 | Subject | Re: [PATCH v3 4/4] arm64: dts: ti: Add support for J784S4 EVM board | From | Andrew Davis <> |
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On 11/18/22 1:27 PM, Nishanth Menon wrote: > On 12:15-20221118, Andrew Davis wrote: >> I don't see either of those addressed in that thread, only that >> the aliases should go in the .dts files and be trimmed, nothing > > Key is trimmed to what the system and ecosystem needs. > >> stops us from: >> >> chosen { >> stdout-path = "serial10:115200n8"; >> }; >> >> aliases { >> serial10 = &main_uart8; >> }; > > Do we need 10 serial aliases? There are'nt 10 serial ports exposed in > j782s2. ok - lets say we do this, then: [1] is needed to boot? but why > do we need to do that for all armv8 platforms when aliases allows us
Why do we need SERIAL_8250_NR_UARTS at all, might be a better question. These should be dynamically allocated if the number goes over the default count imposed by the TTY framework. Maybe folks are still a bit too afraid to touch the TTY subsystem core, I don't blame them..
> to trim it to just the 3 or 4 serial ports the platform really needs > That + being able to use the convention that serial2 is always linux > console, is'nt that a good thing? Hence recommending to just expose the > serialports as aliases to exactly what we need while keeping serial2 as > the linux console (which in this case happens to be main_uart8 - example > as j721s2 does). >
"serial2 as the linux console" is *not* a convention, we just don't want to fix up our bootloader/userspace to actually reason about what serial ports to put logins on. Why not make ttyS10 the default, or ttyS666, it doesn't solve your multi-distro issue either way since they usually only start a login on ttyS0, console=, and/or the first virtual tty. Never on ttyS2. So you are hacking up DT for a solution that doesn't do what you want in the end.
Andrew
> [1] https://lore.kernel.org/lkml/3ab9addf-7938-fcf3-6147-15a998e37d2d@ti.com/ >
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