# Re: \[GIT PULL\] On-demand device probing

- From: Rob Herring \<robh+dt@kernel.org\>
- Date: 2015-10-17 15:19:57 
- List: linux-fbdev
- Page: https://ratatoskr.run/linux-fbdev/2015/10/4600165
- Thread: https://ratatoskr.run/linux-clk/2015/10/4597241/t.md

```text
On Fri, Oct 16, 2015 at 4:23 PM, Olof Johansson [ref] wrote:
> Hi,
>
> I've bisected boot failures in next-20151016 down to patches in this branch:
>
> On Thu, Oct 15, 2015 at 4:42 AM, Tomeu Vizoso
> [ref] wrote:
>> Tomeu Vizoso (20):
>>       driver core: handle -EPROBE_DEFER from bus_type.match()
>
> The machine it happened on was OMAP5UEVM:
>
> http://arm-soc.lixom.net/bootlogs/next/next-20151016/omap5uevm-arm-omap2plus_defconfig.html

So this one is because the MMC node numbering changed. I don't know
how to fix that other than with aliases, but that doesn't solve
backwards compatibility.


> But I've also seen it on tegra2, that one bisected down to:
>
>>      regulator: core: Probe regulators on demand
>
> http://arm-soc.lixom.net/bootlogs/next/next-20151016/seaboard-arm-multi_v7_defconfig.html

This one you need a rootwait I think. The MMC scanning is not
guaranteed to be done before the rootfs mounting AFAIK. There may be
other problems, but we can't see them since it panics.

Rob
```