Re: [beagleboard] Re: [PATCH v7 1/2] Add driver for Aptina (Micron) mt9p031 sensor.

[CJ <cjpostor@gmail.com>]

Hi Laurent,

On 23/08/11 19:47, Laurent Pinchart wrote:
> Hi Chris,
>
> On Tuesday 23 August 2011 05:47:20 CJ wrote:
>> On 22/08/11 22:15, Michael Jones wrote:
>>>>>>> I am trying to get the mt9p031 working from nand with a ubifs file
>>>>>>> system and I am having a few problems.
>>>>>>>
>>>>>>> /dev/media0 is not present unless I run:
>>>>>>> #mknod /dev/media0 c 251 0
>>>>>>> #chown root:video /dev/media0
>>>>>>>
>>>>>>> #media-ctl -p
>>>>>>> Enumerating entities
>>>>>>> media_open: Unable to enumerate entities for device /dev/media0
>>>>>>> (Inappropriate ioctl for device)
>>>>>>>
>>>>>>> With the same rig/files it works fine running from EXT4 on an SD
>>>>>>> card. Any idea why this does not work on nand with ubifs?
>>>>>> Is the OMAP3 ISP driver loaded ? Has it probed the device successfully
>>>>>> ? Check the kernel log for OMAP3 ISP-related messages.
>>>>> Here is the version running from SD card:
>>>>> # dmesg | grep isp
>>>>> [    0.265502] omap-iommu omap-iommu.0: isp registered
>>>>> [    2.986541] omap3isp omap3isp: Revision 2.0 found
>>>>> [    2.991577] omap-iommu omap-iommu.0: isp: version 1.1
>>>>> [    2.997406] omap3isp omap3isp: hist: DMA channel = 0
>>>>> [    3.006256] omap3isp omap3isp: isp_set_xclk(): cam_xclka set to
>>>>> 21600000 Hz
>>>>> [    3.011932] omap3isp omap3isp: isp_set_xclk(): cam_xclka set to 0 Hz
>>>>>
>>>>>    From NAND using UBIFS:
>>>>> # dmesg | grep isp
>>>>> [    3.457061] omap3isp omap3isp: Revision 2.0 found
>>>>> [    3.462036] omap-iommu omap-iommu.0: isp: version 1.1
>>>>> [    3.467620] omap3isp omap3isp: hist: DMA channel = 0
>>>>> [    3.472564] omap3isp omap3isp: isp_set_xclk(): cam_xclka set to
>>>>> 21600000 Hz
>>>>> [    3.478027] omap3isp omap3isp: isp_set_xclk(): cam_xclka set to 0 Hz
>>>>>
>>>>> Seems to be missing:
>>>>> omap-iommu omap-iommu.0: isp registered
>>>>>
>>>>> Is that the issue? Why would this not work when running from NAND?
>>> I'm not sure, either, but I had a similar problem before using Laurent's
>>> patch below. IIRC, usually udev would create /dev/media0 from a cached
>>> list of /dev/*. Later modutils would come along and load the modules in
>>> the proper order (iommu, then omap3-isp) and everybody was happy.
>>> Occasionally, udev would fail to use the cached version of /dev/, and
>>> look through /sys/devices to re-create the devices in /dev/. When media0
>>> was found, omap3-isp.ko would be loaded, but iommu had not yet been,
>>> presumably because it doesn't have an entry in /sys/devices/. So maybe
>>> udev is behaving differently for you on NAND than it did on the card?
>>> Either way, as I said, using Laurent's patch below did the job for me.
>>>
>>>> I'm not sure why it doesn't work from NAND, but the iommu2 module needs
>>>> to be loaded before the omap3-isp module. Alternatively you can compile
>>>> the iommu2 module in the kernel with
>>>>
>>>> diff --git a/arch/arm/plat-omap/Kconfig b/arch/arm/plat-omap/Kconfig
>>>> index 49a4c75..3c87644 100644
>>>> --- a/arch/arm/plat-omap/Kconfig
>>>> +++ b/arch/arm/plat-omap/Kconfig
>>>> @@ -132,7 +132,7 @@ config OMAP_MBOX_KFIFO_SIZE
>>>>
>>>>    	  module parameter).
>>>>
>>>>    config OMAP_IOMMU
>>>>
>>>> -       tristate
>>>> +       bool
>>>>
>>>>    config OMAP_IOMMU_DEBUG
>>>>
>>>>           tristate "Export OMAP IOMMU internals in DebugFS"
>> Thanks for the help!
>>
>> For some reason dmesg does not read early kernel stuff when in UBIFS
>> from NAND.
>> So when I went back and had a look the line I thought was not there is
>> actually included.
>>
>> [    0.276977] omap-iommu omap-iommu.0: isp registered
>>
>> So I guess everything is loading fine.
>>
>> I tried the patch and it didn't make a difference.
>>
>> Regarding what Michael said /dev/media0 is not created by udev when boot
>> from NAND.
>> I tried creating it manually with:
>> #mknod /dev/media0 c 251 0
>> #chown root:video /dev/media0
>>
>> But this does not work - outputs:
>>
>> # media-ctl -r -l '"mt9p031 2-0048":0->"OMAP3 ISP CCDC":0[1], "OMAP3 ISP
>> CCDC":2->"OMAP3 ISP preview":0[1], "OMAP3 ISP preview":1->"OMAP3 ISP
>> resizer":0[1], "OMAP3 ISP resizer":1->"OMAP3 ISP resizer output":0[1]'
>> media_open: Unable to enumerate entities for device /dev/media0
>> (Inappropriate ioctl for device)
>>
>> So is there a problem with udev?
> There could be. What's the output of
>
> ls /sys/class/video4linux
>

#ls /sys/class/video4linux
v4l-subdev0  v4l-subdev3  v4l-subdev6  video0       video3       video6
v4l-subdev1  v4l-subdev4  v4l-subdev7  video1       video4
v4l-subdev2  v4l-subdev5  v4l-subdev8  video2       video5

Cheers,
Chris