Re: [PATCH v7 08/17] ACPI: pci_link: Clear the dependencies after probe
From: Bjorn Helgaas <helgaas@kernel.org>
Date: 2024-07-31 19:49:29
Also in:
linux-pci, linux-riscv, lkml
On Mon, Jul 29, 2024 at 07:52:30PM +0530, Sunil V L wrote:
RISC-V platforms need to use dependencies between PCI host bridge, Link devices and the interrupt controllers to ensure probe order. The dependency is like below. Interrupt controller <-- Link Device <-- PCI Host bridge. If there is no dependency added between Link device and PCI Host Bridge, then the PCI end points can get probed prior to link device, unable to get mapping for INTx.
This sentence is missing a word or something. Maybe it's supposed to say something like this: If there is no dependency between Link device and PCI Host Bridge, then PCI devices may be probed prior to Link devices. If a PCI device is probed before its Link device, we won't be able to find its INTx mapping.
So, add the link device's HID to dependency honor list and also clear it after its probe.
It looks like *this* patch only clears it after probe. And the commit log doesn't say why we need to clear the dependency.
quoted hunk ↗ jump to hunk
Signed-off-by: Sunil V L <sunilvl@ventanamicro.com> --- drivers/acpi/pci_link.c | 2 ++ drivers/acpi/scan.c | 1 + 2 files changed, 3 insertions(+)diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c index aa1038b8aec4..b727db968f33 100644 --- a/drivers/acpi/pci_link.c +++ b/drivers/acpi/pci_link.c@@ -748,6 +748,8 @@ static int acpi_pci_link_add(struct acpi_device *device, if (result) kfree(link); + acpi_dev_clear_dependencies(device); + return result < 0 ? result : 1; }diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 28a221f956d7..753539a1f26b 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c@@ -863,6 +863,7 @@ static const char * const acpi_honor_dep_ids[] = { "INTC10CF", /* IVSC (MTL) driver must be loaded to allow i2c access to camera sensors */ "RSCV0001", /* RISC-V PLIC */ "RSCV0002", /* RISC-V APLIC */ + "PNP0C0F", /* PCI Link Device */ NULL };-- 2.43.0