Disk drive generating feed-forward actuator compensation based on a speaker driver signal

1. A disk drive comprising:

a disk;

a head;

an actuator for actuating the head over the disk; and

control circuitry comprising a servo control system for controlling the actuator, the control circuitry operable to:

generate a compensation value based on a speaker driver signal; and

control the actuator using the compensation value.

2. The disk drive as recited in claim 1 , wherein the actuator is operable to actuate the head radially over the disk.

3. The disk drive as recited in claim 1 , further comprising an interface operable to receive the speaker driver signal from a host.

4. The disk drive as recited in claim 3 , wherein the speaker driver signal comprises an analog signal.

5. The disk drive as recited in claim 4 , wherein the control circuitry is further operable to:

sample the analog signal to generate a digital signal; and

generate the compensation value in response to the digital signal.

6. The disk drive as recited in claim 3 , wherein the speaker driver signal comprises a digital signal.

7. The disk drive as recited in claim 6 , wherein the host converts the digital signal into an analog signal for driving a speaker.

8. The disk drive as recited in claim 1 , wherein the compensation value comprises a feed-forward compensation value.

9. The disk drive as recited in claim 8 , wherein the control circuitry further comprises a feed-forward generator operable to generate the feed-forward compensation value, the control circuitry further operable to:

generate a position error signal (PES) representing a difference between a measured position of the head and a reference position; and

adapt the feed-forward generator based on the speaker driver signal and the PES.

10. The disk drive as recited in claim 9 , wherein the control circuitry is further operable to adapt the feed-forward generator during a calibration procedure when the speaker driver signal comprises a predetermined signal.

11. A method of operating a disk drive comprising a disk, a head, and an actuator for actuating the head over the disk, the method comprising:

generating a compensation value based on a speaker driver signal; and

controlling the actuator using the compensation value.

12. The method as recited in claim 11 , wherein the actuator is operable to actuate the head radially over the disk.

13. The method as recited in claim 12 , further comprising receiving the speaker driver signal from a host.

14. The method as recited in claim 13 , wherein the speaker driver signal comprises an analog signal.

15. The method as recited in claim 14 , further comprising:

sampling the analog signal to generate a digital signal; and

generating the compensation value in response to the digital signal.

16. The method as recited in claim 13 , wherein the speaker driver signal comprises a digital signal.

17. The method as recited in claim 16 , wherein the host converts the digital signal into an analog signal for driving a speaker.

18. The method as recited in claim 11 , wherein the compensation value comprises a feed-forward compensation value.

19. The method as recited in claim 18 , further comprising:

generating a position error signal (PES) representing a difference between a measured position of the head and a reference position; and

adapting a feed-forward generator based on the speaker driver signal and the PES.

20. The method as recited in claim 19 , further comprising adapting the feed-forward generator during a calibration procedure when the speaker driver signal comprises a predetermined signal.