Re: AM3517 fails to boot 3.16-rc5 device tree kernel

[Tony Lindgren <tony@atomide.com>]

* mwelling <mwelling@emacinc.com> [140717 16:42]:
> I am in the process of porting a device tree compatible version of the
> linux kernel to a AM3517 based device.
> 
> First I tried 3.10.x and the device tree port appeared to be incomplete.
> Neither the LCD or Ethernet were supported.
> 
> Next I tried 3.14.x and the Ethernet driver appeared to work but still
> no LCD support.
> 
> Lastly I tried 3.16-rc5 and found that the kernel hangs in early boot
> without any messages from the serial COM.

For device tree based booting on omap3 I would user v.16-rc4 or later.
There have been multiple issues fixed over past year and PM is working
finally at least for 36xx/37xx. And we do have the DSS panels finally
working too.
 
> I was using the omap2plus_defconfig and the am3517-evm.dtb from each
> kernel build. Is there any reason why the kernel would start hanging
> with the newest release?

No reason that I can think of. AFAIK 3517 has been booting in the test
farms just fine?

Can you please enable debug_ll + earlyprintk and pass also earlyprintk
in the kernel cmdline?
 
> Are there any versions where the LCD output works?

Starting with v3.16-rc1 you should get the LCD working for panel-dpi
based devices. Most of them actually are actually ls037v3dw01, so
see omap3-panel-sharp-ls037v7dw01.dtsi and omap3-evm-common.dtsi
variants if you have similar setup.
 
> Looking at the 3.16-rc5 test results just posted it is supposed to be working
> but I have not been able to replicate this.
> 
> Any suggestions would be greatly appreciated.

Hmm maybe double check your're booting device tree based kernel
instead of legacy machine ID based kernel? The legacy booting should
still work just fine and no changes has been made to it, but it will
get removed shortly.

Regards,

Tony