status = "disabled"

[Weiß, Jürgen]

> -----Original Message-----
> From: Nathan Whitehorn [mailto:nwhitehorn at freebsd.org]
> Sent: Sunday, February 02, 2014 4:20 PM
> To: Weiß, Jürgen; freebsd-arm at freebsd.org
> Subject: Re: status = "disabled"
> 
> On 02/02/14 05:55, Weiß, Jürgen wrote:
> > Hi,
> >
> > it seems your recent changes (261351) discarded a call to fdt_is_enabled
> > for devices on simplebus. So 'status = "disabled" ' does not work
> > anymore in arm dts.
> >
> > Regards
> >
> > Juergen Weiss
> >
> > Juergen Weiss      |Universitaet Mainz, Zentrum fuer Datenverarbeitung,
> > weiss at uni-mainz.de |55099 Mainz, Tel: +49(6131)39-26361, FAX: +49(6131)39-26407
> >
> >
> 
> That's actually required to make some hardware work ("disabled" may just
> mean the clock is turned off and needs to be turned back on, which means
> you absolutely do want that device probed). The device drivers
> themselves, not the bus, should be checking this property and
> interpreting it. If this has actually broken hardware, we could add a
> temporary #ifdef __arm__ check to the simplebus tree-walker while the
> relevant drivers get fixed up.
> -Nathan


Thanks for the quick answer. Right know there seem to be zero device drivers
doing this. And there are quite a few fdts going from general (all devices on SOC) 
to specific (devices usable on specific board), which use the status field
to disable a device (for example i.mx in general and wandboard specifically).
At least with the i.mx6 the unconnected sdhci devices lead to hangs during
boot.

Regards

Juergen Weiss

Juergen Weiss      |Universitaet Mainz, Zentrum fuer Datenverarbeitung,
weiss at uni-mainz.de |55099 Mainz, Tel: +49(6131)39-26361, FAX: +49(6131)39-26407