Subject: arm64: dts: qcom: Add t-power-on-us property for PCIe root ports

[PATCH 0/8] Subject: arm64: dts: qcom: Add t-power-on-us property for PCIe root ports

Posted by Krishna Chaitanya Chundru 2 weeks ago

The Qualcomm PCIe host controller driver added support for parsing the
-power-on-us property[1] from each Root Port node and programming it as
art of host initialization (PCI: qcom: Program T_POWER_ON) [2]. Prior to
this, T_POWER_ON was expected to be programmed correctly in hardware or
by the bootloader, but not all targets support this, which can lead to an
incorrectly calculated LTR_L1.2_THRESHOLD in aspm.c and improper L1.2 exit
behavior.

This series adds the t-power-on-us = <80>; property to the PCIe root
port node(s) on the following targets, so the controller programs the
correct T_POWER_ON value instead of relying on the (currently incorrect)
hardware default:

- kodiak
- lemans
- monaco
- hamoa
- glymur
- talos
- sm8750
- kaanapali

[1] https://lore.kernel.org/all/20260205093346.667898-1-krishna.chundru@oss.qualcomm.com/
[2] https://lore.kernel.org/all/20260428-t_power_on_fux-v5-0-f1ef926a91ff@oss.qualcomm.com/

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
---
Krishna Chaitanya Chundru (8):
      arm64: dts: qcom: kodiak: Add t-power-on-us property for PCIe root ports
      arm64: dts: qcom: lemans: Add t-power-on-us property for PCIe root ports
      arm64: dts: qcom: monaco: Add t-power-on-us property for PCIe root ports
      arm64: dts: qcom: hamoa: Add t-power-on-us property for PCIe root ports
      arm64: dts: qcom: glymur: Add t-power-on-us property for PCIe root ports
      arm64: dts: qcom: talos: Add t-power-on-us property for PCIe root port
      arm64: dts: qcom: sm8750: Add t-power-on-us property for PCIe root port
      arm64: dts: qcom: kaanapali: Add t-power-on-us property for PCIe root port

 arch/arm64/boot/dts/qcom/glymur.dtsi    | 8 ++++++++
 arch/arm64/boot/dts/qcom/hamoa.dtsi     | 8 ++++++++
 arch/arm64/boot/dts/qcom/kaanapali.dtsi | 2 ++
 arch/arm64/boot/dts/qcom/kodiak.dtsi    | 4 ++++
 arch/arm64/boot/dts/qcom/lemans.dtsi    | 4 ++++
 arch/arm64/boot/dts/qcom/monaco.dtsi    | 4 ++++
 arch/arm64/boot/dts/qcom/sm8750.dtsi    | 2 ++
 arch/arm64/boot/dts/qcom/talos.dtsi     | 2 ++
 8 files changed, 34 insertions(+)
---
base-commit: 08df884136f1c1197bab2a27814404fd329d9aac
change-id: 20260911-t_pwr_on-069f454ebb23

Best regards,
--  
Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>

Re: [PATCH 0/8] Subject: arm64: dts: qcom: Add t-power-on-us property for PCIe root ports

Posted by Manivannan Sadhasivam 2 weeks ago

On Fri, Sep 11, 2026 at 12:18:51PM +0530, Krishna Chaitanya Chundru wrote:
> The Qualcomm PCIe host controller driver added support for parsing the
> -power-on-us property[1] from each Root Port node and programming it as
> art of host initialization (PCI: qcom: Program T_POWER_ON) [2]. Prior to
> this, T_POWER_ON was expected to be programmed correctly in hardware or
> by the bootloader, but not all targets support this, which can lead to an
> incorrectly calculated LTR_L1.2_THRESHOLD in aspm.c and improper L1.2 exit
> behavior.
> 
> This series adds the t-power-on-us = <80>; property to the PCIe root
> port node(s) on the following targets, so the controller programs the
> correct T_POWER_ON value instead of relying on the (currently incorrect)
> hardware default:
> 
> - kodiak
> - lemans
> - monaco
> - hamoa
> - glymur
> - talos
> - sm8750
> - kaanapali
> 
> [1] https://lore.kernel.org/all/20260205093346.667898-1-krishna.chundru@oss.qualcomm.com/
> [2] https://lore.kernel.org/all/20260428-t_power_on_fux-v5-0-f1ef926a91ff@oss.qualcomm.com/
> 
> Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>

Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

- Mani

-- 
மணிவண்ணன் சதாசிவம்

[PATCH 1/8] arm64: dts: qcom: kodiak: Add t-power-on-us property for PCIe root ports