[Letux-kernel] LX20 prototype is booting

[H. Nikolaus Schaller]

> Am 05.05.2025 um 21:35 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
> 
> I think I should better debug the gpio-keys irq issue next. It is quite easily
> repeatable by pressing teh WKUP button. Then, kernel stops and LEDs don't blink.
> Unless I release and then everything continues.

Result of another trial:

permanently calls gpio_keys_gpio_isr while button is pressed.

And it is indeed an interrupt with falling and rising edge trigger:

https://elixir.bootlin.com/linux/v6.1.28/source/drivers/input/keyboard/gpio_keys.c#L601
https://elixir.bootlin.com/linux/v6.15-rc5/source/drivers/input/keyboard/gpio_keys.c#L596

What I wonder is why it works on neither of both kernel. In the first we have no special
x1600 patch and for the latter we have added one to solve exactly this problem for x1600.

So it should work on one and not on the other... Or two bugs have the same result.

Or another idea: it never worked in sudomaker-kernels for x2000. The halley5.dts doesn't use it at
all.

For the exec() problem I could now trace it down to arch_check_elf() in arch/mips/kernel/elf.c
And specifically:

	https://elixir.bootlin.com/linux/v6.1.28/source/arch/mips/kernel/elf.c#L166

But I have no idea why. And why only for x2000 and not x1600.

Values are:

[    0.017085] arch_check_elf elf32=1
[    0.017085] arch_check_elf flags=10001007

which means that EF_MIPS_NAN2008 (=0x00000400) is not set in the flags.
And mips_use_nan_legacy is not set at all.

So either the header is not read properly (alignment issue?) or the mips_use_nan_legacy
should be set... Which may be correct that it is not set. Then we have a problem.

BR,
Nikolaus