Hi Laurent and Michael,

On 22/08/11 22:15, Michael Jones wrote:

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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.

-Michael

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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?

Cheers,
Chris