hint.uart.1 in device.hints causes freeze at boot

[Lundberg, Johannes]

Hi Marcel

Switching to PCI does not help the halting boot, only disabling UART1 does.

I'm working with UART0 (in PCI mode with Adafruit cable) to get serial
console output but all I get is garbage (question marks with filled
elliptic background) from BIOS. When kernel is loaded output stops.

Where did you get this info?
hw.uart.console="mm:0xd0810000,br:115200,rs:2,xo:44236800

The only info I can find is that this address is for the sound chip(?)..

Even though HDMI is working out of the box it would be nice to also have
serial console for when you don't wanna carry around a big monitor...


On Sat, Feb 27, 2016 at 9:22 AM, Marcel Moolenaar <marcel at xcllnt.net> wrote:

>
> On Feb 27, 2016, at 5:54 AM, Lundberg, Johannes <
> johannes at brilliantservice.co.jp> wrote:
>
> >though I've no clue why or how that should cause a boot failure?
>
> Verbose logging don't give any clues either.. It just stops.
>
>
> On the Atom SoC I have, you can configure the UARTs as PCI or ACPI devices.
> They work as PCI devices but required better support for memory mapped low-
> level consoles in x86. If configured as ACPI (supposedly compatible), they
> just
> don’t work. I belief FreeBSD would just hang when configured as ACPI, but
> I’m
> foggy on that detail.
>
> Key is that they we’re trimmed-down UARTs (3-wire functionality) and thus
> weird
> beasts...
>
> Johannes: If your BIOS has the same capability, try switching. PCI mode is
> well
> supported in FreeBSD, though requires something like the following in your
> loader.conf:
>
> hw.uart.console="mm:0xd0810000,br:115200,rs:2,xo:44236800
>
> This tells the uart(4) driver that the device is memory mapped (at I/O
> address 0xd0810000, uses 32-bit register access and has a non-standard
> clock input of 44236800 (=44Mhz).
>
> --
> Marcel Moolenaar
> marcel at xcllnt.net
>
>

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