[PATCH v2] ARM: dts: am33xx: Move the cppi41dma node so it's probed early

Ezequiel García ezequiel at vanguardiasur.com.ar
Thu May 8 10:00:36 PDT 2014

Hi George,

On 29 April 2014 04:58, George Cherian <george.cherian at ti.com> wrote:
> On 4/29/2014 11:49 AM, Yegor Yefremov wrote:
>> On Thu, Apr 24, 2014 at 11:11 PM, Ezequiel Garcia
>> <ezequiel at vanguardiasur.com.ar> wrote:
>>> The DMA controller is needed for the USB controller to be correctly
>>> registered. Therefore, if the DMA node is located at the end an
>>> unecessary
>>> probe deferral is produced systematically.
>>> This is easily fixed by moving the node at the beggining of the child
>>> list,
>>> so it's probed first.
> This will give issues on module removal.
> Since we use device_for_each_child in remove patch, it will try to remove
> cppi dma controller, while the channel
> is still in use by musb node.

OK, this seems confusing: are you sure module removal works?

Doing this simple test on v3.15-rcN:

$ modprobe musb_dsps
$ modprobe musb_am335x
$ modprobe musb_am335x -r

And the kernel blows up :-(

I've been debugging this and I think we simply cannot support removal
of the musb_am335x

Had this ever worked before?
Ezequiel García, VanguardiaSur

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