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tk_sus_dev

Suspend Device

[C Language Interface]





INT cnt = tk_sus_dev ( UINT mode ) ;

[Parameters]

UINT	mode	Mode
[Return Parameters]

INT	cnt	Suspend disable request count


	or	Error code
[Error Codes]

E_BUSY	Suspend already disabled


E_QOVR	Suspend disable request count limit exceeded
[Description]

Performs the processing specified in mode, then passes the resulting suspend disable request count in the return code.

mode := ( (TD_SUSPEND | TD_FORCE) || TD_DISSUS || TD_ENASUS || TD_CHECK)


#define	TD_SUSPEND	0x0001	/* suspend	*/
#define	TD_DISSUS	0x0002	/* disable suspension	*/
#define	TD_ENASUS	0x0003	/* enable suspension	*/
#define	TD_CHECK	0x0004	/* get suspend disable request count	*/
#define	TD_FORCE	0x8000	/* forcibly suspend	*/

TD_SUSPEND Suspend

If suspending is enabled, suspends processing. If suspending is disabled, returns E_BUSY.

TD_SUSPEND | TD FORCE Forcibly suspend

Suspends even in suspend disabled state.

TD_DISSUS Disable suspension

Disables suspension.

TD_ENASUS Enable suspension

Enables suspension.

If the enable request count is greater than the disable count for the resource group, no operation is performed.

TD_CHECK Get suspend disable count

Gets only the number of times suspend disable has been requested.

Suspension is performed in the following steps.

1. Suspension processing in non-disk devices

2. Suspension processing in disk devices

3. SUSPEND state entered

Resumption from SUSPEND state is performed in the following steps.

1. Return from SUSPEND state

2. Resumption processing in disk devices

3. Resumption processing in non-disk devices

The number of suspend disable requests is counted. Suspension is enabled only if the same number of suspend enable requests are made. At system boot, the suspend disable count is 0 and suspension is enabled. There is only one suspend disable request count kept per system, but the system keeps track of the resource group making the request. It is not possible to clear suspend disable requests made in another resource group. When the cleanup function runs in a resource group, all the suspend requests made in that group are cleared and the suspend disable request count is reduced accordingly. The upper limit of suspend-disabled request count is implementation-defined, but the count can be executed up to at least 255. When the upper limit is exceeded, E_QOVR is returned.

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