linux-kernel - Re: [PATCH] PCI / ACPI: Make acpiphp ignore root bridges using PCIe native hotplug

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Date:	Tue, 25 Oct 2011 22:10:16 +0900
From:	Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
CC:	Linux PCI <linux-pci@...r.kernel.org>,
	Jesse Barnes <jbarnes@...tuousgeek.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux PM list <linux-pm@...r.kernel.org>,
	ACPI Devel Mailing List <linux-acpi@...r.kernel.org>,
	Matthew Garrett <mjg59@...f.ucam.org>
Subject: Re: [PATCH] PCI / ACPI: Make acpiphp ignore root bridges using PCIe
 native hotplug

Looks good.
This is also needed for SHPC native hotplug.

Regards,
Kenji Kaneshige


(2011/10/22 7:43), Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki<rjw@...k.pl>
>
> If the kernel has requested control of the PCIe native hotplug
> feature for a given root complex, the acpiphp driver should not try
> to handle that root complex and it should leave it to pciehp.
> Failing to do so causes problems to happen if acpiphp is loaded
> before pciehp on such systems.
>
> To address this issue make find_root_bridges() ignore PCIe root
> complexes with PCIe native hotplug enabled and make add_bridge()
> return error code if PCIe native hotplug is enabled for the given
> root port.  This causes acpiphp to refuse to load if PCIe native
> hotplug is enabled for all complexes and to refuse binding to
> the root complexes with PCIe native hotplug is enabled.
>
> Signed-off-by: Rafael J. Wysocki<rjw@...k.pl>
> ---
>   drivers/pci/hotplug/acpiphp_glue.c |   29 ++++++++++++++++++++++++-----
>   1 file changed, 24 insertions(+), 5 deletions(-)
>
> Index: linux/drivers/pci/hotplug/acpiphp_glue.c
> ===================================================================
> --- linux.orig/drivers/pci/hotplug/acpiphp_glue.c
> +++ linux/drivers/pci/hotplug/acpiphp_glue.c
> @@ -458,8 +458,17 @@ static int add_bridge(acpi_handle handle
>   {
>   	acpi_status status;
>   	unsigned long long tmp;
> +	struct acpi_pci_root *root;
>   	acpi_handle dummy_handle;
>
> +	/*
> +	 * We shouldn't use this bridge if PCIe native hotplug control has been
> +	 * granted by the BIOS for it.
> +	 */
> +	root = acpi_pci_find_root(handle);
> +	if (root&&  (root->osc_control_set&  OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
> +		return -ENODEV;
> +
>   	/* if the bridge doesn't have _STA, we assume it is always there */
>   	status = acpi_get_handle(handle, "_STA",&dummy_handle);
>   	if (ACPI_SUCCESS(status)) {
> @@ -1297,13 +1306,23 @@ static void handle_hotplug_event_func(ac
>   static acpi_status
>   find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
>   {
> +	struct acpi_pci_root *root;
>   	int *count = (int *)context;
>
> -	if (acpi_is_root_bridge(handle)) {
> -		acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
> -				handle_hotplug_event_bridge, NULL);
> -			(*count)++;
> -	}
> +	if (!acpi_is_root_bridge(handle))
> +		return AE_OK;
> +
> +	root = acpi_pci_find_root(handle);
> +	if (!root)
> +		return AE_OK;
> +
> +	if (root->osc_control_set&  OSC_PCI_EXPRESS_NATIVE_HP_CONTROL)
> +		return AE_OK;
> +
> +	(*count)++;
> +	acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
> +				    handle_hotplug_event_bridge, NULL);
> +
>   	return AE_OK ;
>   }
>
> --
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