SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549

                                 SCHEDULE 13G


                                 (Rule 13d-102)


             INFORMATION STATEMENT PURSUANT TO RULES 13d-1 AND 13d-2


                   Under the Securities Exchange Act of 1934
                               (Amendment No. 3)


                               GENESIS MICROCHIP INC
             -----------------------------------------------------
                                (Name of Issuer)
                                  Common Stock
              -----------------------------------------------------
                         (Title of Class of Securities)

                                   371933102
             -----------------------------------------------------
                                 (CUSIP Number)



Check the following box if a fee is being paid with this statement [].


----------
*The remainder of this cover page shall be filled out for a reporting  person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise  subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).



CUSIP No. 371933102        13G                    Page 2  of 8 Pages



--------------------------------------------------------------------------------
   1.  NAME OF REPORTING PERSON(S)
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON(S)

       Morgan  Stanley  Dean  Witter &  Co.
       IRS  #  39-314-5972
--------------------------------------------------------------------------------
   2.  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                             (a)  [  ]
                                                             (b)  [  ]
--------------------------------------------------------------------------------
   3.  SEC USE ONLY


--------------------------------------------------------------------------------
   4.  CITIZENSHIP OR PLACE OF ORGANIZATION

       The state of organization is Delaware.
--------------------------------------------------------------------------------
   NUMBER OF      5.   SOLE VOTING POWER
     SHARES            0
  BENEFICIALLY    --------------------------------------------------------------
    OWNED BY      6.   SHARED VOTING POWER
      EACH             922,689
   REPORTING      --------------------------------------------------------------
     PERSON       7.   SOLE DISPOSITIVE POWER
      WITH
                  --------------------------------------------------------------
                  8.   SHARED DISPOSITIVE POWER
                       922,814
--------------------------------------------------------------------------------
   9.  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

       922,814
--------------------------------------------------------------------------------
  10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*


--------------------------------------------------------------------------------
  11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

       4.3868%
--------------------------------------------------------------------------------
  12.  TYPE OF REPORTING PERSON*

       IA, CO
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!


CUSIP No. 371933102    13G                                Page 3  of  8  Pages



--------------------------------------------------------------------------------
   1.  NAME OF REPORTING PERSON(S)
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON(S)

       Morgan Stanley Investment Management Inc.
       IRS  #  13-3040307
--------------------------------------------------------------------------------
   2.  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                             (a)  [  ]
                                                             (b)  [  ]
--------------------------------------------------------------------------------
   3.  SEC USE ONLY


--------------------------------------------------------------------------------
   4.  CITIZENSHIP OR PLACE OF ORGANIZATION

       The state of organization is Delaware.
--------------------------------------------------------------------------------
   NUMBER OF      5.   SOLE VOTING POWER
     SHARES             0
  BENEFICIALLY    --------------------------------------------------------------
    OWNED BY      6.   SHARED VOTING POWER
      EACH             0
   REPORTING      --------------------------------------------------------------
     PERSON       7.   SOLE DISPOSITIVE POWER
      WITH              0
                  --------------------------------------------------------------
                  8.   SHARED DISPOSITIVE POWER
                       125
--------------------------------------------------------------------------------
   9.  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

       125
--------------------------------------------------------------------------------
  10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*


--------------------------------------------------------------------------------
  11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
       .0006%
--------------------------------------------------------------------------------
  12.  TYPE OF REPORTING PERSON*

       IA, CO
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!



--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!


CUSIP No. 371933102           13G                           Page 4  of 8 Pages



Item 1.     (a)   Name of Issuer:
                  GENESIS MICROCHIP INC
                  --------------------------------------------------------------
            (b)   Address of Issuer's Principal Executive Offices:
                  2150 GOLD
                  THORNHILL
                  ONTARIO, CANADA L3T 7V8
                  --------------------------------------------------------------
Item 2.     (a)   Name of Person Filing:
                  (a) Morgan Stanley Dean Witter & Co.
                  (b) Morgan Stanley Investment Management Inc.
                  --------------------------------------------------------------
            (b)   Address of Principal Business Office, or if None, Residence:

                  (a) 1585 Broadway
                      New  York, New  York 10036

                  (b) 1221 Avenue of the Americas
                      New York, New York 10020
                  --------------------------------------------------------------
            (c)   Citizenship:

                  Incorporated by reference to Item 4 of the
                  cover page pertaining to each reporting person.
                  --------------------------------------------------------------
            (d)   Title of Class of Securities:
                  Common Stock
                  --------------------------------------------------------------
            (e)   CUSIP Number:
                  371933102
                  --------------------------------------------------------------

Item 3.     (a)   Morgan Stanley Dean Witter & Co. is a parent holding company.

            (b)   Morgan Stanley Investment Management Inc. is
                  an Investment Adviser registered under Section 203 of the
                  Investment Advisers Act of 1940.





CUSIP No. 371933102  13-G                                Page 5  of  8  Pages



Item 4.     Ownership.

            Incorporated by reference to Items  (5) - (9) and (11) of the
            cover page.

Item 5.     Ownership of Five Percent or Less of a Class.

            Inapplicable.

Item 6.     Ownership of More Than Five Percent on Behalf of Another Person.

            (a)     As of the date hereof, Morgan Stanley Dean Witter and Co.
                    has ceased to be the beneficial owner of more than five
                    percent of the class of securities.

            (b)     As of the date hereof, Morgan Stanley Investment Management
                    Inc. has ceased to be the beneficial owner of more than
                    five percent of the class of securities.


Item 7.     Identification and Classification of the Subsidiary which Acquired
            the Security Being Reported on By the Parent Holding Company.

Item 8.     Identification and Classification of Members of the Group.

Item 9.     Notice of Dissolution of Group.

Item 10.    Certification.

            By signing below I certify that, to the best of my knowledge and
            belief, the securities referred to above were acquired in the
            ordinary course of business and were not acquired for the purpose
            of and do not have the effect of changing or influencing the
            control of the issuer of such securities and were not acquired in
            connection with or as a participant in any transaction having
            such purpose or effect.


CUSIP No. 371933102     13-G                              Page 6  of  8 Pages


                                  Signature.


            After reasonable inquiry and to the best of my knowledge and
            belief, I certify that the information set forth in this
            statement is true, complete and correct.


Date:       March 11, 2002

Signature:  /s/ Dennine Bullard
            -----------------------------------------------------------------

Name/Title  Dennine Bullard /Vice President, Morgan Stanley & Co. Incorporated
            -----------------------------------------------------------------
            MORGAN STANLEY DEAN WITTER & CO.


Date:       March 11, 2002

Signature:  /s/ James P. Wallin
            -----------------------------------------------------------------

Name/Title  James Wallin /Executive Director, Morgan Stanley Investment
                          Management Inc.
            -----------------------------------------------------------------
            MORGAN STANLEY INVESTMENT MANAGEMENT INC.




                      INDEX TO EXHIBITS                             PAGE
                      -----------------                             ----

EXHIBIT 1       Agreement to Make a Joint Filing                       7

EXHIBIT 2       Secretary's Certificate Authorizing Dennine Bullard 8
                to Sign on behalf of Morgan Stanley Dean Witter & Co.


               *  Attention.  Intentional  misstatements  or  omissions  of fact
               constitute federal criminal violations (see 18 U.S.C. 1001).

(022597DTI)

                   EX-99
            JOINT FILING AGREEMENT



CUSIP No. 371933102           13-G                        Page 7  of  8 Pages


                            EXHIBIT 1 TO SCHEDULE 13G
               ---------------------------------------------------


                              MARCH 11, 2002
               ---------------------------------------------------


            MORGAN STANLEY DEAN WITTER & CO. And MORGAN STANLEY

            INVESTMENT MANAGEMENT INC. hereby agree that, unless

            differentiated, this Schedule 13G is filed on behalf of

            each of the parties.


            MORGAN STANLEY DEAN WITTER & CO.

            BY: /s/ Dennine Bullard
            --------------------------------------------------------------------
            Dennine Bullard /Vice President, Morgan Stanley & Co. Incorporated

            MORGAN STANLEY INVESTMENT MANAGEMENT INC.

            BY: /s/ James P. Wallin
            --------------------------------------------------------------------
            James P. Wallin /Executive Director, Morgan Stanley Investment
                             Management Inc.



* Attention. Intentional misstatements or omissions of fact constitute federal
  criminal violations (see 18 U.S.C. 1001).


                   EX-99
              SECRETARY'S CERTIFICATE



                                                             Page 8 of 8 pages
                                  EXHIBIT 2                   ------------------

                 MORGAN STANLEY, DEAN WITTER, DISCOVER & CO.

                           SECRETARY'S CERTIFICATE


         I, Charlene R. Herzer, a duly elected and Assistant Secretary
         of Morgan Stanley Dean Witter & Co., a corporation organized and
         existing under the laws of the State of Delaware (the
         "Corporation"), certify that Stuart J.M. Breslow, Robert G. Koppenol
         and Dennine  Bullard are authorized to sign reports to be filed under
         Sections 13 and 16 of the Securities  Exchange Act of 1934 (the "Act")
         pursuant to the following:

             (1)      On May 31, 1997, the Board of Directors of the
                      Corporation granted authority to Stuart J.M.
                      Breslow and Robert G. Koppenol to sign reports to be
                      filed under Sections 13 and 16 of the Act on behalf of
                      the Corporation.

             (2)      On February 23, 2000, Donald G. Kempf, Jr., the Executive
                      Vice President, Chief Legal Officer and Secretary of the
                      Corporation, delegated  authority to Dennine Bullard to
                      sign reports to be filed under Sections 13 and 16 of the
                      Act on behalf of the  Corporation.  Pursuant to Section
                      7.01 of the Bylaws of the Corporation and resolutions
                      approved by the Board of Directors of the Corporation on
                      September 25, 1998, the Chief Legal Officer is authorized
                      to enter into agreements and other instruments on behalf
                      of the Corporation and may delegate such powers to others
                      under his jurisdiction.

          IN WITNESS WHEREOF, I have hereunto set my name and affixed the seal
          of the Corporation as of the 1st day of March, 2000.

                                                ______________________________
                                                Charlene R. Herzer
                                                Assistant Secretary