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

[Michael Welling <mwelling@emacinc.com>]

On Fri, Jul 18, 2014 at 09:40:48AM -0500, Michael Welling wrote:
> On Fri, Jul 18, 2014 at 1:38 AM, Tony Lindgren <tony@atomide.com> wrote:
> > * 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?
> I will try this.

Adding the earlyprintk did not work. It still hangs without any
messages.

> >
> >> 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.

How do you determine which you are booting?

> I downloaded the version from the test results and it did boot.
> These are combining the uImage and dtb. How do you accomplish this?
> >
> > Regards,
> >
> > Tony