Idle power mode for external storage device

1. An external storage device configured to connect to a host device, the external storage device comprising:

storage media configured to store one or more data files;

a data interface configured to connect to the host device;

a media controller configured to execute firmware of the external storage device, the media controller further configured to manage read and write operations on the storage media; and

a bridge controller configured to manage the data interface, the bridge controller further configured to:

in response to receiving an idle status message from the media controller during a time period in which the media controller is in an unlocked status and no further communications are received from the host device:

save state data including the unlocked status of the media controller; and

send a shutdown command to the media controller to stop the media controller from using power; and

in response to receiving a read operation or a write operation from the host device:

startup power to the media controller;

provide the media controller with the saved state data to enable the media controller be restored to the unlocked status;

receive first data responsive to the read operation or the write operation from the media controller; and

transmit the first data to the host device;

wherein, in the unlocked status, a user password does not need to be re-provided to access the storage media.

2. The external storage device of claim 1 , wherein sending the shutdown command comprises sending a cache flush command.

3. The external storage device of claim 1 , wherein the media controller is further configured to:

after completing background operations and in the absence of read or write operations from the host device, send the idle status message to the bridge controller.

4. The external storage device of claim 3 , wherein the background operations comprise at least one of:

a cache flush from a buffer of the external storage device to the storage media; or

a self-test to determine a performance level or reliability level of the external storage device.

5. The external storage device of claim 1 , wherein the bridge controller is further configured to save auto-unlock data that includes a user password or a derivative of the user password.

6. The external storage device of claim 1 , further comprising a solid-state drive (SSD), the SSD comprising the storage media and the media controller.

7. The external storage device of claim 6 , wherein the SSD comprises a standard 3.5 inch or M.2 form factor.

8. The external storage device of claim 1 , further comprising a hard disk drive (HDD), the HDD comprising the storage media and the media controller.

9. The external storage device of claim 8 , wherein the HDD comprises a standard 3.5 inch or 5.25 form factor.

10. The external storage device of claim 1 , wherein the external storage device is an unpowered portable drive with a universal serial bus (USB) port.

11. The external storage device of claim 10 , wherein:

the data interface comprises the USB port; and

the bridge controller is further configured to translate from a protocol supported by the media controller to a USB protocol supported by the host device.

12. A method for reducing idle power usage of a storage device, the storage device comprising a media controller, a data interface configured to connect to a host device, storage media, and a bridge controller, the method comprising:

in response to receiving, at the bridge controller, an idle status message from the media controller during a time period in which the media controller is in an unlocked status and no further communications are received from the host device:

saving state data including the unlocked status of the media controller;

sending a shutdown command to the media controller; and

shutting down power to the media controller; and

in response to receiving, at the bridge controller, a read operation or a write operation from the host device:

starting power to the media controller;

providing the media controller with the saved state data to enable the media controller to be restored to the unlocked status;

receiving first data responsive to the read operation or the write operation from the media controller; and

transmitting the first data to the host device;

wherein, in the unlocked status, a user password does not need to be re-provided to access the storage media.

13. The method of claim 12 , wherein sending the shutdown command comprises sending a cache flush command.

14. The method of claim 13 , wherein the cache flush command causes the media controller to:

transfer data from a buffer of the storage device to storage media of the storage device.

15. The method of claim 12 , wherein the media controller is configured to:

after completing background operations and in the absence of read or write operations from the host device, send the idle status message to the bridge controller.

16. The method of claim 15 , wherein the background operations comprise at least one of:

a cache flush from a buffer of the storage device to storage media of the storage device;

a folding operation from higher speed memory of the storage device to lower speed memory of the storage device; or

a self-test to determine a performance level or reliability level of the storage device.

17. The method of claim 12 , wherein the storage device is an unpowered portable drive with a universal serial bus (USB) port.

18. The method of claim 12 , further comprising saving auto-unlock data that includes a user password or a derivative of the user password.

19. The method of claim 12 , wherein in the unlocked status the first data stored in the storage media is accessible by the host device.

20. An external storage device configured to connect to a host device, the external storage device comprising:

means for storing one or more data files;

means for connecting to the host device;

a media controller configured to execute firmware of the external storage device, the media controller further configured to manage read and write operations of the means for storing; and

a bridge controller configured to manage the means for connecting, the bridge controller further configured to:

in response to receiving an idle status message from the media controller during a time period in which the media controller is in an unlocked status and no further communications are received from the host device:

save state data including the unlocked status of the media controller; and

send a shutdown command to the media controller to stop the media controller from using power; and

in response to receiving a read operation or a write operation from the host device:

startup power to the media controller;

provide the media controller with the saved state data to enable the media controller to be restored to the unlocked status;

receive first data responsive to the read operation or the write operation from the media controller; and

transmit the first data to the host device;

wherein, in the unlocked status, a user password does not need to be re-provided to access the means for storing.