[meta-freescale] mxc_v4l2_capture sometimes not being modprobed

John Weber rjohnweber at gmail.com
Thu Jun 5 11:23:01 PDT 2014

On 6/5/14, 1:17 PM, Otavio Salvador wrote:
> On Thu, Jun 5, 2014 at 3:14 PM, John Weber <rjohnweber at gmail.com> wrote:
>> On 6/5/14, 1:08 PM, Otavio Salvador wrote:
>>> On Thu, Jun 5, 2014 at 3:05 PM, John Weber <rjohnweber at gmail.com> wrote:
>>>> On 6/5/14, 12:34 PM, Otavio Salvador wrote:
>>>>> On Mon, May 26, 2014 at 12:42 AM, John Weber <rjohnweber at gmail.com>
>>>>> wrote:
>>>>>> meta-freescalers:
>>>>>> I'm seeing a behavior that I can't easily explain.  I'm not seeing the
>>>>>> mxc_v4l2_capture drivers and dependent ipu drivers being automatically
>>>>>> modprobed on Wandboard during a majority of system startups (but not
>>>>>> all).
>>>>>> I was under the impression that this should be done by udev, but for
>>>>>> some
>>>>>> reason it seems to either fail or is skipped.
>>>>>> I can force the driver to be loaded at startup by adding the name of
>>>>>> the
>>>>>> driver in a line in /etc/modules.  This works to load the driver every
>>>>>> time
>>>>>> at startup, but I'm fairly certain that this is not the most ideal
>>>>>> approach
>>>>>> because (A) I have to write a recipe to make the change to /etc/modules
>>>>>> and
>>>>>> (B) it does not explain why the driver load works sometimes, but not
>>>>>> all
>>>>>> of
>>>>>> the time.
>>>>>> Any ideas?
>>>>> Does this happens with 3.0.35 and 3.10.17?
>>>> I did notice it on both kernels.  From what I've been able to gather
>>>> after
>>>> sending this email, the modules load at first boot on a freshly burned
>>>> rootfs (that hasn't been postinst'd).  After that, SW and HW resets and
>>>> POR
>>>> to not result in loaded mxc_v4l2_capture module or its dependencies.  I
>>>> do
>>>> have other modules loaded, however, all the time - the ov5640_mipi driver
>>>> and the Broadcom WLAN drivers load without fail.
>>>> I suspect it could be a sequencing problem, but adding the line to
>>>> /etc/modules fixes it.
>>> Are you using udev-cache?
>> I believe so:
>> root at wandboard-dual:/etc# find . -name *udev-cache*
>> ./rcS.d/S36udev-cache
>> ./default/udev-cache
>> ./init.d/udev-cache
> Disable it in default, please, and check if it helps.
That did it.  Thanks!  Not sure how to fix the problem though.

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