linux-kernel - Re: [Patch v5 7/7] acpi_memhotplug.c: auto bind the memory device which is hotplugged before the driver is loaded

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Date:	Thu, 15 Nov 2012 18:57:06 +0900
From:	Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
To:	Wen Congyang <wency@...fujitsu.com>
CC:	<linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>,
	<linux-acpi@...r.kernel.org>, Len Brown <len.brown@...el.com>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Lai Jiangshan <laijs@...fujitsu.com>,
	Jiang Liu <jiang.liu@...wei.com>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Minchan Kim <minchan.kim@...il.com>,
	Mel Gorman <mgorman@...e.de>,
	David Rientjes <rientjes@...gle.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Toshi Kani <toshi.kani@...com>, Jiang Liu <liuj97@...il.com>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Paul Mackerras <paulus@...ba.org>,
	Christoph Lameter <cl@...ux.com>
Subject: Re: [Patch v5 7/7] acpi_memhotplug.c: auto bind the memory device
 which is hotplugged before the driver is loaded

2012/11/15 15:59, Wen Congyang wrote:
> If the memory device is hotplugged before the driver is loaded, the user
> cannot see this device under the directory /sys/bus/acpi/devices/, and the
> user cannot bind it by hand after the driver is loaded.  This patch
> introduces a new feature to bind such device when the driver is being
> loaded.
> 
> CC: David Rientjes <rientjes@...gle.com>
> CC: Jiang Liu <liuj97@...il.com>
> CC: Len Brown <len.brown@...el.com>
> CC: Benjamin Herrenschmidt <benh@...nel.crashing.org>
> CC: Paul Mackerras <paulus@...ba.org>
> CC: Christoph Lameter <cl@...ux.com>
> Cc: Minchan Kim <minchan.kim@...il.com>
> CC: Andrew Morton <akpm@...ux-foundation.org>
> CC: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
> CC: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
> CC: Rafael J. Wysocki <rjw@...k.pl>
> CC: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> Signed-off-by: Wen Congyang <wency@...fujitsu.com>
> ---

Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>

Thanks,
Yasuaki Ishimatsu

>   drivers/acpi/acpi_memhotplug.c | 37 ++++++++++++++++++++++++++++++++++++-
>   1 file changed, 36 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
> index e0f7425..9f1d107 100644
> --- a/drivers/acpi/acpi_memhotplug.c
> +++ b/drivers/acpi/acpi_memhotplug.c
> @@ -52,6 +52,9 @@ MODULE_LICENSE("GPL");
>   #define MEMORY_POWER_ON_STATE	1
>   #define MEMORY_POWER_OFF_STATE	2
>   
> +static bool auto_probe;
> +module_param(auto_probe, bool, S_IRUGO | S_IWUSR);
> +
>   static int acpi_memory_device_add(struct acpi_device *device);
>   static int acpi_memory_device_remove(struct acpi_device *device, int type);
>   
> @@ -494,12 +497,44 @@ acpi_memory_register_notify_handler(acpi_handle handle,
>   				    u32 level, void *ctxt, void **retv)
>   {
>   	acpi_status status;
> -
> +	struct acpi_memory_device *mem_device = NULL;
> +	unsigned long long current_status;
>   
>   	status = is_memory_device(handle);
>   	if (ACPI_FAILURE(status))
>   		return AE_OK;	/* continue */
>   
> +	if (auto_probe) {
> +		/* Get device present/absent information from the _STA */
> +		status = acpi_evaluate_integer(handle, "_STA", NULL,
> +					       &current_status);
> +		if (ACPI_FAILURE(status))
> +			goto install;
> +
> +		/*
> +		 * Check for device status. Device should be
> +		 * present/enabled/functioning.
> +		 */
> +		if (!(current_status &
> +		      (ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED |
> +		       ACPI_STA_DEVICE_FUNCTIONING)))
> +			goto install;
> +
> +		if (acpi_memory_get_device(handle, &mem_device))
> +			goto install;
> +
> +		/* We have bound this device while we register the driver */
> +		if (mem_device->state == MEMORY_POWER_ON_STATE)
> +			goto install;
> +
> +		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
> +				  "\nauto probe memory device\n"));
> +
> +		if (acpi_memory_enable_device(mem_device))
> +			pr_err(PREFIX "Cannot enable memory device\n");
> +	}
> +
> +install:
>   	status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
>   					     acpi_memory_device_notify, NULL);
>   	/* continue */
> 


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