From: Bjorn Helgaas <helgaas@kernel.org>
To: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
Cc: "Viresh Kumar" <vireshk@kernel.org>, "Nishanth Menon" <nm@ti.com>,
"Stephen Boyd" <sboyd@kernel.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
"Manivannan Sadhasivam" <mani@kernel.org>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Bjorn Andersson" <andersson@kernel.org>,
"Konrad Dybcio" <konradybcio@kernel.org>,
"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
"Conor Dooley" <conor+dt@kernel.org>,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, linux-arm-msm@vger.kernel.org,
devicetree@vger.kernel.org
Subject: Re: [PATCH v5 5/5] PCI: qcom: Use frequency and level based OPP lookup
Date: Wed, 29 Oct 2025 15:39:48 -0500 [thread overview]
Message-ID: <20251029203948.GA1585122@bhelgaas> (raw)
In-Reply-To: <20251013-opp_pcie-v5-5-eb64db2b4bd3@oss.qualcomm.com>
On Mon, Oct 13, 2025 at 04:23:32PM +0530, Krishna Chaitanya Chundru wrote:
> PCIe link configurations such as 8GT/s x2 and 16GT/s x1 may operate at
> the same frequency but differ in other characteristics like RPMh votes.
> The existing OPP selection based solely on frequency cannot distinguish
> between such cases.
>
> In such cases, frequency alone is insufficient to identify the correct OPP.
> Use the newly introduced dev_pm_opp_find_key_exact() API to match both
> frequency and level when selecting an OPP, here level indicates PCIe
> data rate.
>
> To support older device tree's where opp-level is not defined, check if
> opp-level is present or not using dev_pm_opp_find_level_exact(). if
> not present fallback to frequency only match.
What are the names of the DT properties here for the exact (frequency
+ level) and frequency-only values? I'd like to mention them in the
commit log so we can look at a DT and figure out what to expect from
this change.
next prev parent reply other threads:[~2025-10-29 20:39 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-13 10:53 [PATCH v5 0/5] OPP: Add support to find OPP for a set of keys Krishna Chaitanya Chundru
2025-10-13 10:53 ` [PATCH v5 1/5] arm64: dts: qcom: sm8450: Add opp-level to indicate PCIe data rates Krishna Chaitanya Chundru
2025-10-13 10:53 ` [PATCH v5 2/5] arm64: dts: qcom: sm8550: " Krishna Chaitanya Chundru
2025-10-13 10:53 ` [PATCH v5 3/5] arm64: dts: qcom: sm8650: " Krishna Chaitanya Chundru
2025-10-13 10:53 ` [PATCH v5 4/5] arm64: dts: qcom: x1e80100: " Krishna Chaitanya Chundru
2025-10-13 10:53 ` [PATCH v5 5/5] PCI: qcom: Use frequency and level based OPP lookup Krishna Chaitanya Chundru
2025-10-22 16:37 ` Konrad Dybcio
2025-10-26 16:26 ` Manivannan Sadhasivam
2025-10-29 20:39 ` Bjorn Helgaas [this message]
2025-10-31 6:28 ` Manivannan Sadhasivam
2025-10-26 16:25 ` (subset) [PATCH v5 0/5] OPP: Add support to find OPP for a set of keys Manivannan Sadhasivam
2025-10-26 16:27 ` Manivannan Sadhasivam
2025-10-27 22:37 ` (subset) " Bjorn Andersson
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