Re: [BUG] Error applying setting, reverse things back on lot of devices

From: Ahmad Fatoum <a.fatoum@pengutronix.de>
To: "Michał Mirosław" <mirq-linux@rere.qmqm.pl>,
	"Corentin Labbe" <clabbe.montjoie@gmail.com>
Cc: lgirdwood@gmail.com, mripard@kernel.org,
	linux-kernel@vger.kernel.org, wens@csie.org, broonie@kernel.org,
	linux-arm-kernel@lists.infradead.org,
	"linux-stm32@st-md-mailman.stormreply.com" 
	<linux-stm32@st-md-mailman.stormreply.com>
Subject: Re: [BUG] Error applying setting, reverse things back on lot of devices
Date: Mon, 2 Nov 2020 13:48:54 +0100	[thread overview]
Message-ID: <8a580d12-fa4a-6cd8-4d82-3e3b784e348b@pengutronix.de> (raw)
In-Reply-To: <20201024115307.GA2745@qmqm.qmqm.pl>

Hello Michał,

CC += linux-stm32

On 10/24/20 1:53 PM, Michał Mirosław wrote:
> On Fri, Oct 23, 2020 at 10:39:43PM +0200, Corentin Labbe wrote:
>> On Fri, Oct 23, 2020 at 03:42:01PM +0200, Corentin Labbe wrote:
>>> On Wed, Oct 21, 2020 at 08:31:49PM +0200, Corentin Labbe wrote:
>>> I have just saw thoses 3 lines which are probably the real problem.
>>> I have started a new bisect with this error, but it is hitting the same "crash range" the first one.
>>>
>>
>> I have bisected the problem to commit aea6cb99703e17019e025aa71643b4d3e0a24413 ("regulator: resolve supply after creating regulator")
>> Reverting this fix my problem.

The change broke boot on all the STM32MP1 boards, because the STPMIC driver
has a vref_ddr regulator, which does not have a dedicated supply, but without
a vref_ddr-supply property the system now no longer boots.

> Can you try the hack below?
> 
> Best Regards,
> Michał Mirosław
> 
> diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
> index a4ffd71696da..9ad091f5f1ab 100644
> --- a/drivers/regulator/core.c
> +++ b/drivers/regulator/core.c
> @@ -1169,6 +1169,9 @@ static int machine_constraints_voltage(struct regulator_dev *rdev,
>  		}
>  
>  		if (current_uV < 0) {
> +			if (current_uV == -EINVAL && rdev->supply_name)
> +				return -EPROBE_DEFER;
> +

This doesn't fix the issue for the STM32MP1 boards (tested on LXA MC-1).
Seeing that the patch is already in stable, I think this patch should be
reverted until the issues are solved in Linus' master.

Cheers,
Ahmad

>  			rdev_err(rdev,
>  				 "failed to get the current voltage: %pe\n",
>  				 ERR_PTR(current_uV));
> 
> _______________________________________________
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> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

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