[Letux-kernel] 4.14-rc* on Pyra/OMAP5EVM

[Tony Lindgren]

Hi,

* H. Nikolaus Schaller <hns at goldelico.com> [171010 12:29]:
> Now after several days of work I have a result:
> 
> 	There are only 'skip'ped commits left to test.
> 	The first bad commit could be any of:
> 	d2b310b0234c20a656e2b9047b6f2a318ad39c35
> 	fc23beb8a57723eecd04cd732e0722df72feaf70
> 
> Let's look into them:
> 
> 	https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d2b310b0234c20a656e2b9047b6f2a318ad39c35
> 	https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fc23beb8a57723eecd04cd732e0722df72feaf70
> 
> Both have indeed something to do with OMAP3/4/5 UARTs.
> 
> So this explains why there is no console message after they are applied, i.e. between v4.1 and v4.14-rc1.
> 
> But it does not explain:
> * why it works on GTA04 (OMAP3)
> * why the kernel doesn't start at all (no LEDs blinking) on omap5432uevm (or Pyra)

Hmm OK that explains, sorry to hear about wasting time on this :(

The 8250 based DEBUG_LL uart will maintain the .config values for UART address
etc. So just disable CONFIG_DEBUG_LL in all your configs and use the earlycon
instead. DEBUG_LL is not portable across machines and should be only selected
if nothing else helps.

$ grep "config DEBUG_UART_" arch/arm/Kconfig.debug
config DEBUG_UART_PL01X
config DEBUG_UART_8250
config DEBUG_UART_PHYS
config DEBUG_UART_VIRT
config DEBUG_UART_8250_SHIFT
config DEBUG_UART_8250_WORD
config DEBUG_UART_8250_PALMCHIP
config DEBUG_UART_8250_FLOW_CONTROL

You probably enabled these for GTA04, and those addresses will hang early
on anything else.

Regards,

Tony