Re: How to printk unsigned long long variable?

["jidong xiao" <jidong.xiao@gmail.com>]

dma_mask should be a pointer, I mean, the element in struct device, see below,

struct device {
	struct list_head node;		/* node in sibling list */
	struct list_head bus_list;	/* node in bus's list */
	struct list_head driver_list;
	struct list_head children;
	struct device 	* parent;

	struct kobject kobj;
	char	bus_id[BUS_ID_SIZE];	/* position on parent bus */

	struct bus_type	* bus;		/* type of bus device is on */
	struct device_driver *driver;	/* which driver has allocated this
					   device */
	void		*driver_data;	/* data private to the driver */
	void		*platform_data;	/* Platform specific data (e.g. ACPI,
					   BIOS data relevant to device) */
	struct dev_pm_info	power;

	u32		detach_state;	/* State to enter when device is
					   detached from its driver. */

	u64		*dma_mask;	/* dma mask (if dma'able device) */
	u64		coherent_dma_mask;/* Like dma_mask, but for
					     alloc_coherent mappings as
					     not all hardware supports
					     64 bit addresses for consistent
					     allocations such descriptors. */

	struct list_head	dma_pools;	/* dma pools (if dma'ble) */

	struct dma_coherent_mem	*dma_mem; /* internal for coherent mem
					     override */

	void	(*release)(struct device * dev);
};


Regards
Jason Xiao

On 6/16/07, Roland Dreier <rdreier@cisco.com> wrote:
>  > Is this right?
>
>  >        dev->dev.dma_mask = bus->controller->dma_mask;
>  >        printk(KERN_ERR "hey,jason,see,dma_mask is
>  > %llu\n",*(dev->dev.dma_mask));
>
> No, why do you have the '*' -- dma_mask isn't a pointer, is it?
>
> You probably want:
>
>        printk(KERN_ERR "hey,jason,see,dma_mask is %llx\n",
>               (unsigned long long) dev->dev.dma_mask);
>
> (I would use a "%llx" format because masks are much clearer in hex).
> The cast to unsigned long long is there because u64 is just unsigned
> long on some 64-bit platforms, so you get a warning about the format
> not matching on some architectures without the cast.
>
>  - R.
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