serial: of-serial: fetch line number from DT
l.stach at pengutronix.de
Tue Nov 11 02:37:39 PST 2014
Am Montag, den 10.11.2014, 14:38 -0700 schrieb Stephen Warren:
> On 11/10/2014 02:34 PM, Olof Johansson wrote:
> > Greg,
> > This commit:
> > commit 1bd8324535ec1ff44aef55c0e40b9e7d56b310fb
> > Author: Lucas Stach <dev at lynxeye.de>
> > Date: Mon Nov 3 23:16:54 2014 +0100
> > serial: of-serial: fetch line number from DT
> > Broke a whole lot of tegra boards in last night's -next here. In
> > particular, I've been looking at tegra20-seaboard, which now doesn't
> > boot with console any more.
> > http://arm-soc.lixom.net/bootlogs/next/next-20141110/
> > Unfortunately, tegra has for a long time been specifying the aliases
> > as a fixed 1:1 mapping, but most environments rely on ttyS0 being the
> > first _activated_ serial port. That's obviously going to break things
> > here. :(
> > Stephen: I suppose the best way to handle this on tegra is to specify
> > the aliases per-board instead of in the soc dtsi today.
> IIRC, there was a deliberate request to name the Tegra UARTs after the
> SoC ports rather than board ports, so that it'd be obvious to people
> which port was which. I'm not sure if we can change the aliases in the
> Tegra DTs now that people may have got used to them?
First off: sorry for breaking stuff.
The point of this patch was exactly to have a common naming scheme
between bootloader and and kernel. The aliases provide this in a broadly
Relying on the fact that ttyS0 maps to the debug UART seems extremely
fragile and the fact that this patch broke this assumption actually
IMHO it is a bug in U-Boot that it doesn't look at the aliases when it
builds the console= kernel parameter. But I recognize the problem that
this change introduces a non-backward compatible break between firmware
and kernel and I don't yet see a nice solution for this.
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Industrial Linux Solutions | http://www.pengutronix.de/ |
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