linux-kernel - Re: [PATCH] pmdomain: samsung: Fix splash-screen handover by enforcing a sync

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Message-ID: <751b912d-48a5-416d-aa83-8947b952dd5e@samsung.com>
Date: Fri, 11 Jul 2025 14:59:05 +0200
From: Marek Szyprowski <m.szyprowski@...sung.com>
To: Ulf Hansson <ulf.hansson@...aro.org>, linux-pm@...r.kernel.org
Cc: Krzysztof Kozlowski <krzk@...nel.org>, Alim Akhtar
	<alim.akhtar@...sung.com>, linux-arm-kernel@...ts.infradead.org,
	linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] pmdomain: samsung: Fix splash-screen handover by
 enforcing a sync_state

On 11.07.2025 13:47, Ulf Hansson wrote:
> It's has been reported that some Samsung platforms fails to boot with
> genpd's new sync_state support.
>
> Typically the problem exists for platforms where bootloaders are turning on
> the splash-screen and handing it over to be managed by the kernel. However,
> at this point, it's not clear how to correctly solve the problem.
>
> Although, to make the platforms boot again, let's add a temporary hack in
> the samsung power-domain provider driver, which enforces a sync_state that
> allows the power-domains to be reset before consumer devices starts to be
> attached.
>
> Reported-by: Marek Szyprowski <m.szyprowski@...sung.com>
> Link: https://lore.kernel.org/all/212a1a56-08a5-48a5-9e98-23de632168d0@samsung.com
> Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>

This fixes the issue and seems to be a good workaround for now. Thanks!

Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>

I will work on the proper fix in 2 weeks after getting back from holidays.


> ---
>   drivers/pmdomain/samsung/exynos-pm-domains.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
>
> diff --git a/drivers/pmdomain/samsung/exynos-pm-domains.c b/drivers/pmdomain/samsung/exynos-pm-domains.c
> index 9b502e8751d1..5d478bb37ad6 100644
> --- a/drivers/pmdomain/samsung/exynos-pm-domains.c
> +++ b/drivers/pmdomain/samsung/exynos-pm-domains.c
> @@ -147,6 +147,15 @@ static int exynos_pd_probe(struct platform_device *pdev)
>   				parent.np, child.np);
>   	}
>   
> +	/*
> +	 * Some Samsung platforms with bootloaders turning on the splash-screen
> +	 * and handing it over to the kernel, requires the power-domains to be
> +	 * reset during boot. As a temporary hack to manage this, let's enforce
> +	 * a sync_state.
> +	 */
> +	if (!ret)
> +		of_genpd_sync_state(np);
> +
>   	pm_runtime_enable(dev);
>   	return ret;
>   }

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland