linux-kernel - Re: [PATCH v2] ACPI: pci_root: Clear the acpi dependencies after PCI root bridge initialization on RISC-V

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Message-ID: <CAJZ5v0ixBFGHwvSEp3Ae_s0tyhK338Gju=1+vb+O3_pH2mHyGA@mail.gmail.com>
Date: Tue, 27 Jan 2026 16:00:49 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: huyuye <huyuye812@....com>, Bjorn Helgaas <bhelgaas@...gle.com>
Cc: Sunil V L <sunilvl@...tanamicro.com>, Paul Walmsley <pjw@...nel.org>, 
	Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>, 
	Alexandre Ghiti <alex@...ti.fr>, Robert Moore <robert.moore@...el.com>, linux-pci@...r.kernel.org, 
	linux-acpi@...r.kernel.org, linux-riscv@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, dai.hualiang@....com.cn, 
	deng.weixian@....com.cn, guo.chang2@....com.cn, liu.qingtao2@....com.cn, 
	wu.jiabao@....com.cn, lin.yongchun@....com.cn, hu.yuye@....com.cn, 
	zhang.longxiang@....com.cn, zuo.jiang@....com.cn, li.kunpeng@....com.cn
Subject: Re: [PATCH v2] ACPI: pci_root: Clear the acpi dependencies after PCI
 root bridge initialization on RISC-V

On Mon, Jan 12, 2026 at 3:17 PM huyuye <huyuye812@....com> wrote:
>
> Hi Rafael,
> Thank you for your thorough review and valuable comments on v1.
> I've updated the patch as follows:
> 1. Removed the redundant #ifdef CONFIG_ACPI and if (!acpi_disabled)
> guard as you pointed out. The entire code block indeed already depends
> on CONFIG_ACPI at a higher level, making the inner guard unnecessary.
> 2. Moved acpi_dev_clear_dependencies to RISC-V specific architecture
> code (driver/acpi/riscv/acpi_pci.c). This ensures that ACPI dependency
> clearing is handled within the appropriate architectural context.
>
> Best regards
> Signed-off-by: huyuye <huyuye812@....com>
> ---
>  drivers/acpi/pci_root.c       |  6 ++++++
>  drivers/acpi/riscv/Makefile   |  2 +-
>  drivers/acpi/riscv/acpi_pci.c | 11 +++++++++++
>  include/acpi/acpi_bus.h       |  1 +
>  4 files changed, 19 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/acpi/riscv/acpi_pci.c
>
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index 9d7f85dadc48..a16eb9097cdc 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -30,6 +30,11 @@ static int acpi_pci_root_add(struct acpi_device *device,
>                              const struct acpi_device_id *not_used);
>  static void acpi_pci_root_remove(struct acpi_device *device);
>
> +
> +void __weak arch_acpi_pci_root_add_clear_dep(struct acpi_device *device)
> +{
> +}
> +
>  static int acpi_pci_root_scan_dependent(struct acpi_device *adev)
>  {
>         acpiphp_check_host_bridge(adev);
> @@ -760,6 +765,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
>         pci_lock_rescan_remove();
>         pci_bus_add_devices(root->bus);
>         pci_unlock_rescan_remove();
> +       arch_acpi_pci_root_add_clear_dep(device);

Actually, this could be as simple as

       if (IS_ENABLED(CONFIG_RISCV))
              acpi_dev_clear_dependencies(device);

with a brief comment explaining why it is needed.

Bjorn, any thoughts?

>         return 1;
>
>  remove_dmar:
> diff --git a/drivers/acpi/riscv/Makefile b/drivers/acpi/riscv/Makefile
> index 1284a076fa88..5b1bd0298fb9 100644
> --- a/drivers/acpi/riscv/Makefile
> +++ b/drivers/acpi/riscv/Makefile
> @@ -1,5 +1,5 @@
>  # SPDX-License-Identifier: GPL-2.0-only
> -obj-y                                  += rhct.o init.o irq.o
> +obj-y                                  += rhct.o init.o irq.o acpi_pci.o
>  obj-$(CONFIG_ACPI_PROCESSOR_IDLE)      += cpuidle.o
>  obj-$(CONFIG_ACPI_CPPC_LIB)            += cppc.o
>  obj-$(CONFIG_ACPI_RIMT)                        += rimt.o
> diff --git a/drivers/acpi/riscv/acpi_pci.c b/drivers/acpi/riscv/acpi_pci.c
> new file mode 100644
> index 000000000000..368ff113e5c6
> --- /dev/null
> +++ b/drivers/acpi/riscv/acpi_pci.c
> @@ -0,0 +1,11 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2026, ZTE Corporation
> + *  Author: Yu Ye Hu <hu.yuye@....com.cn>
> + */
> +#include <linux/acpi.h>
> +
> +void arch_acpi_pci_root_add_clear_dep(struct acpi_device *device)
> +{
> +       acpi_dev_clear_dependencies(device);
> +}
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index aad1a95e6863..c00b523a6ebd 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -996,6 +996,7 @@ int acpi_wait_for_acpi_ipmi(void);
>
>  int acpi_scan_add_dep(acpi_handle handle, struct acpi_handle_list *dep_devices);
>  u32 arch_acpi_add_auto_dep(acpi_handle handle);
> +void arch_acpi_pci_root_add_clear_dep(struct acpi_device *device);
>  #else  /* CONFIG_ACPI */
>
>  static inline int register_acpi_bus_type(void *bus) { return 0; }
> --
> 2.43.0
>