linux-kernel - Re: [PATCH v8 12/22] PCI, ACPI: debug print for installation of acpi root bridge's notifier

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Message-ID: <2183351.x1cn8B59bl@vostro.rjw.lan>
Date:	Sun, 13 Jan 2013 00:37:57 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Yinghai Lu <yinghai@...nel.org>
Cc:	Bjorn Helgaas <bhelgaas@...gle.com>, Len Brown <lenb@...nel.org>,
	Taku Izumi <izumi.taku@...fujitsu.com>,
	Jiang Liu <jiang.liu@...wei.com>, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
	Tang Chen <tangchen@...fujitsu.com>
Subject: Re: [PATCH v8 12/22] PCI, ACPI: debug print for installation of acpi root bridge's notifier

On Friday, January 11, 2013 02:40:39 PM Yinghai Lu wrote:
> From: Tang Chen <tangchen@...fujitsu.com>
> 
> acpi_install_notify_handler() could fail. So check the exit status
> and give a better debug info.
> 
> Signed-off-by: Tang Chen <tangchen@...fujitsu.com>
> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
> ---
>  drivers/acpi/pci_root.c |   12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index d30fb94..862abcc 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -943,6 +943,7 @@ static bool acpi_is_root_bridge_object(acpi_handle handle)
>  static acpi_status __init
>  find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
>  {
> +	acpi_status status;
>  	char objname[64];
>  	struct acpi_buffer buffer = { .length = sizeof(objname),
>  				      .pointer = objname };
> @@ -955,9 +956,14 @@ find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
>  
>  	acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
>  
> -	acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
> -				handle_hotplug_event_root, NULL);
> -	printk(KERN_DEBUG "acpi root: %s notify handler installed\n", objname);
> +	status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
> +					handle_hotplug_event_root, NULL);
> +	if (ACPI_FAILURE(status))
> +		printk(KERN_DEBUG "acpi root: %s notify handler is not installed, exit status: %u\n",
> +				  objname, (unsigned int)status);

If we print a message on failure, I don't think we need one on success.

Besides, please use pr_debug().

> +	else
> +		printk(KERN_DEBUG "acpi root: %s notify handler is installed\n",
> +				 objname);
>  
>  	add_acpi_root_bridge(handle);

And I wonder what sens does this make to call add_acpi_root_bridge() here if we
haven't installed the notify handler for handle?

Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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