linux-kernel - Re: [PATCH] PCI: qcom: Use OPP only if the platform supports it

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Message-ID: <20240813202456.GB1922056@rocinante>
Date: Wed, 14 Aug 2024 05:24:56 +0900
From: Krzysztof Wilczyński <kw@...ux.com>
To: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
Cc: lpieralisi@...nel.org, robh@...nel.org, bhelgaas@...gle.com,
	linux-arm-msm@...r.kernel.org, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] PCI: qcom: Use OPP only if the platform supports it

Hello,

> With commit 5b6272e0efd5 ("PCI: qcom: Add OPP support to scale
> performance"), OPP was used to control the interconnect and power domains
> if the platform supported OPP. Also to maintain the backward compatibility
> with platforms not supporting OPP but just ICC, the above mentioned commit
> assumed that if ICC was not available on the platform, it would resort to
> OPP.
> 
> Unfortunately, some old platforms don't support either ICC or OPP. So on
> those platforms, resorting to OPP in the absence of ICC throws below errors
> from OPP core during suspend and resume:
> 
> qcom-pcie 1c08000.pcie: dev_pm_opp_set_opp: device opp doesn't exist
> qcom-pcie 1c08000.pcie: _find_key: OPP table not found (-19)
> 
> Also, it doesn't make sense to invoke the OPP APIs when OPP is not
> supported by the platform at all. So let's use a flag to identify whether
> OPP is supported by the platform or not and use it to control invoking the
> OPP APIs.

Applied to controller/qcom, thank you!

[1/1] PCI: qcom: Use OPP only if the platform supports it
      https://git.kernel.org/pci/pci/c/d0fa8ca89100

	Krzysztof