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Date: Thu, 28 Dec 2023 10:28:01 +0000
From: Sudeep Holla <sudeep.holla@arm.com>
To: Konrad Dybcio <konrad.dybcio@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Lorenzo Pieralisi <lpieralisi@kernel.org>,
	Marijn Suijten <marijn.suijten@somainline.org>,
	linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
	Bjorn Andersson <andersson@kernel.org>
Subject: Re: [PATCH 2/2] firmware/psci: Set
 pm_set_resume/suspend_via_firmware() on qcom
Message-ID: <20231228102801.fzaubcjq5thfwgxg@bogus>
References: <20231227-topic-psci_fw_sus-v1-0-6910add70bf3@linaro.org>
 <20231227-topic-psci_fw_sus-v1-2-6910add70bf3@linaro.org>
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In-Reply-To: <20231227-topic-psci_fw_sus-v1-2-6910add70bf3@linaro.org>

On Wed, Dec 27, 2023 at 11:15:31PM +0100, Konrad Dybcio wrote:
> Most Qualcomm platforms implementing PSCI (ab)use CPU_SUSPEND for
> entering various stages of suspend, across the SoC. These range from a
> simple WFI to a full-fledged power collapse of the entire chip
> (mostly, anyway).
> 
> Some device drivers are curious to know whether "the firmware" (which is
> often assumed to be ACPI) takes care of suspending or resuming the
> platform. Set the flag that reports this behavior on the aforementioned
> chips.
> 
> Some newer Qualcomm chips ship with firmware that actually advertises
> PSCI SYSTEM_SUSPEND, so the compatible list should only grow slightly.
>

NACK, just use suspend-to-idle if SYSTEM_SUSPEND is not advertised. It is
designed for such platforms especially on x86/ACPI which don't advertise
Sx states. I see no reason why that doesn't work on ARM platforms as well.

-- 
Regards,
Sudeep