[U-Boot] 2015.10-rc2 Chromebook Snow boot failure

[Misha Komarovskiy]

Hello Simon,
Confirmed, with vdd_arm set 1.1, snow boots fine.
---
Best Regards,
Misha Komarovskiy
zombahatgmaildotcom


On Mon, Aug 24, 2015 at 12:31 PM, Misha Komarovskiy <zombah at gmail.com> wrote:
> Hello Simon,
> 2015.07 and 2015.10-rc1 both boot fine. I use this U-Boot as third
> stage from SD card/USB stick, im not quite
> sure what right name for this position from reset vector.
> I will try to increase  ret = exynos_set_regulator("vdd_arm",
> 1000000); to 1100000 and report result.
> ---
> Best Regards,
> Misha Komarovskiy
> zombahatgmaildotcom
>
>
> On Mon, Aug 24, 2015 at 12:21 AM, Simon Glass <sjg at chromium.org> wrote:
>> Hi,
>>
>> On 21 August 2015 at 09:55, Misha Komarovskiy <zombah at gmail.com> wrote:
>>> Hello,
>>> I have failure in attempt to boot Chromebook Snow with 2015.10-rc2
>>> build snow_defconfig, here is error message, it maybe not full as i
>>> have some noise on serial console with device:
>>>
>>> U-Boot 2015.10-rc2 (Aug 21 2015 - 15:43:43 +0000) for snow
>>> GPU:   Exynos5250 @ 1.7 GHz
>>> Model: Google Snow
>>> Board: Google Snow
>>> DRAM:  2 GiB
>>> ERROR: read error from device: bad39118 register: 0x1e!
>>> at drivers/power/pmic/max77686.c:44/max77686_read()
>>> initcall sequence bfdaf3bc failed at call 43e0418c (err=-5)
>>> ### ERROR ### Please RESET the board ###
>>
>> Register 1e is the BUCK3 voltage - see max77686.h.
>>
>> I don't get the same addresses as you but I suppose we are using
>> different toolchains.
>>
>> But this is probably being called from exynos_power_init().
>>
>> The ARM voltage is set to 1.0V. I wonder if that is borderline? We
>> could increase it perhaps to 1.1V. - See the exynos_set_regulator()
>> line for vdd_arm.
>>
>> It was previous 1.3V in 2015.07 - see max77686_init().
>>
>> Are you starting U-Boot SPL directly from the reset vector?
>>
>> Regards,
>> Simon