bug in autoloading of imx-ipuv3-crtc

[Dennis Gilmore]

On Thursday, April 21, 2016 12:37:28 PM CDT Dennis Gilmore wrote:
> On Thursday, April 21, 2016 1:03:17 AM CDT Uwe Kleine-König wrote:
> > Hello,
> > 
> > On Tue, Apr 19, 2016 at 03:16:01PM -0500, Dennis Gilmore wrote:
> > > On Tuesday, April 19, 2016 2:27:17 PM CDT Dennis Gilmore wrote:
> > > > On Tuesday, April 19, 2016 7:50:49 PM CDT Russell King - ARM Linux
> 
> wrote:
> > > > > On Tue, Apr 19, 2016 at 01:34:23PM -0500, Dennis Gilmore wrote:
> > > > > > on all of my i.MX6 systems imx-ipuv3-crtc ius not getting
> > > > > > automatically
> > > > > > loaded.  Everything is built as a module
> > > > > > 
> > > > > > CONFIG_DRM_IMX=m
> > > > > > CONFIG_DRM_IMX_FB_HELPER=m
> > > > > > CONFIG_DRM_IMX_HDMI=m
> > > > > > CONFIG_DRM_IMX_IPUV3=m
> > > > > > CONFIG_DRM_IMX_LDB=m
> > > > > > CONFIG_DRM_IMX_PARALLEL_DISPLAY=m
> > > > > > CONFIG_DRM_IMX_TVE=m
> > > > > > CONFIG_IMX_IPUV3_CORE=m
> > > > > > 
> > > > > > The result is that until I log in via serial or ssh and modprobe
> > > > > > the
> > > > > > module there is no display.  I suspect that there is some
> > > > > > devicetree
> > > > > > glue missing 4.4 and 4.5 seem to both be effected.
> > > > > 
> > > > > DT doesn't come into it for imx-ipuv3-crtc - these platform devices
> > > > > are
> > > > > created by drivers/gpu/ipu-v3/ipu-common.c itself.
> > > > > 
> > > > > drivers/gpu/drm/imx/ipuv3-crtc.c contains the proper module alias
> > > > > which
> > > > > should result in the module loaded at boot time when the
> > > > > imx-ipuv3-crtc
> > > > > devices are created.
> > > > > 
> > > > > Could the problem be that imx-ipu-v3 isn't being loaded?  However,
> > > > > again,
> > > > > it looks to me like everything is correct there.
> > > > > 
> > > > > Are you saying that this used to work in older kernel versions like
> > > > > 4.3,
> > > > > but stopped in 4.4?
> > > > 
> > > > yers it used to work and stopped working. I would need to go back and
> > > > test
> > > > old kernels to figure out where it broke.
> > > 
> > > after installing some old kernels it broke with 4.4-rc4 which included a
> > > patch with teh subject of "drm/imx: Remove of_node assignment from
> > > ipuv3-crtc driver probe"
> > 
> > Just to be sure: 4.4-rc4 with 407c9eba7897 ("drm/imx: Remove of_node
> > assignment from ipuv3-crtc driver probe") reverted works fine for you?
> 
> I can confirm that reverting just that patch makes things work again

Sorry I missed that due to an old kernel package bug the dtb was not in place 
and a different than expected kernel booted.  reverting the one patch is not 
sufficient

Dennis

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