HDMI and kernel warnings...

Using an Arrow Beaglebone Black Industrial board with kernel 4.4.80. This board replaced the TDA998x framer chip with an ADV7511 (I assume for temp rating?) and I am getting kernel warnings when the video driver loads. It appears that TILCDC is loading a ADIHDMI driver to output video via HDMI. I get frame buffer video ok, as I am running a Qt app using the linuxfb and I see the display just fine.

However, if I unplug the HDMI cable, or power down the display and power it back on…the HDMI output goes away. It will not come back. If I try this on 4.1.13 kernel, it works fine. I suspect the issue is related to the kernel warning I see when the ADIHDMI driver is being loaded. I need HDMI to tolerate powerdown of the display device. Here is the warning on bootup:

[ 9.337549] c_can_platform 481cc000.can: c_can_platform device registered (regs=fa1cc000, irq=165)
[ 9.357943] omap_rng 48310000.rng: OMAP Random Number Generator ver. 20
[ 9.385110] ------------[ cut here ]------------
[ 9.391726] WARNING: CPU: 0 PID: 197 at drivers/gpu/drm/drm_crtc.c:5079 drm_mode_connector_attach_encoder+0x47/0x50()
[ 9.391737] Modules linked in: c_can_platform omap_rng c_can rng_core tilcdc(+) can_dev adihdmi evdev leds_gpio uio_pdrv_genirq uio
[ 9.391783] CPU: 0 PID: 197 Comm: systemd-udevd Not tainted 4.4.80+ #71
[ 9.391786] Hardware name: Generic AM33XX (Flattened Device Tree)
[ 9.391820] [] (unwind_backtrace) from [] (show_stack+0x11/0x14)
[ 9.391833] [] (show_stack) from [] (dump_stack+0x69/0x78)
[ 9.391847] [] (dump_stack) from [] (warn_slowpath_common+0x69/0x90)
[ 9.391857] [] (warn_slowpath_common) from [] (warn_slowpath_null+0x17/0x1c)
[ 9.391866] [] (warn_slowpath_null) from [] (drm_mode_connector_attach_encoder+0x47/0x50)
[ 9.391901] [] (drm_mode_connector_attach_encoder) from [] (adihdmi_bind+0xd0/0xfc [adihdmi])
[ 9.391930] [] (adihdmi_bind [adihdmi]) from [] (component_bind_all+0x8d/0x178)
[ 9.391999] [] (component_bind_all) from [] (tilcdc_load+0x34a/0x44c [tilcdc])
[ 9.392037] [] (tilcdc_load [tilcdc]) from [] (drm_dev_register+0x75/0x7c)
[ 9.392051] [] (drm_dev_register) from [] (drm_platform_init+0x35/0xa8)
[ 9.392077] [] (drm_platform_init) from [] (tilcdc_bind+0x18/0x1c [tilcdc])
[ 9.392103] [] (tilcdc_bind [tilcdc]) from [] (try_to_bring_up_master.part.0+0x77/0xa4)
[ 9.392114] [] (try_to_bring_up_master.part.0) from [] (component_master_add_with_match+0x81/0xbc)
[ 9.392139] [] (component_master_add_with_match) from [] (tilcdc_pdev_probe+0x3e/0x78 [tilcdc])
[ 9.392168] [] (tilcdc_pdev_probe [tilcdc]) from [] (platform_drv_probe+0x37/0x7c)
[ 9.392178] [] (platform_drv_probe) from [] (driver_probe_device+0x193/0x340)
[ 9.392187] [] (driver_probe_device) from [] (__driver_attach+0x51/0x54)
[ 9.392199] [] (__driver_attach) from [] (bus_for_each_dev+0x51/0x80)
[ 9.392209] [] (bus_for_each_dev) from [] (bus_add_driver+0x14b/0x1bc)
[ 9.392217] [] (bus_add_driver) from [] (driver_register+0x39/0x8c)
[ 9.392241] [] (driver_register) from [] (tilcdc_drm_init+0x34/0x3f [tilcdc])
[ 9.392270] [] (tilcdc_drm_init [tilcdc]) from [] (do_one_initcall+0xa9/0x198)
[ 9.392286] [] (do_one_initcall) from [] (do_init_module+0x4d/0x2fc)
[ 9.392309] [] (do_init_module) from [] (load_module+0x164d/0x1ac0)
[ 9.392322] [] (load_module) from [] (SyS_finit_module+0x67/0x8c)
[ 9.392337] [] (SyS_finit_module) from [] (ret_fast_syscall+0x1/0x52)
[ 9.417493] —[ end trace 0000000000000002 ]—
[ 9.417658] tilcdc 4830e000.lcdc: bound 0-0039 (ops adihdmi_ops [adihdmi])
[ 9.417680] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[ 9.417690] [drm] No driver support for vblank timestamp query.
[ 10.078169] Console: switching to colour frame buffer device 240x67
[ 10.204268] tilcdc 4830e000.lcdc: fb0: frame buffer device

I diff’d the adihdmi_drv.c between the kernels and there is only a 1 line change. I have tried the .conf from the 4.1.13 kernel build on the 4.4.80 build and same result. I have tried my SD card with the 4.4.80 kernel and config on a regular beagebone black (using the TDA998x framer) and it works perfectly…no warnings…no HDMI going away. So I suspect the issue is the driver for the 7511, but it works on kernel 4.1.13?

Does anyone have any ideas? Thx!