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Bug in backlight MDD driver from Microsoft RRS feed

  • Question

  • Hi,

    I use Windows Embedded Compact 2013 and found a bug in the Microsoft implementation from the backlight-Driver MDD-part.

    In the file “<_WINCEROOT>\public\common\oak\drivers\backlight\mdd\backlight_mdd.cpp” is in the function “IOControl” any unknown IOCTL forwarded to the PDD-part. The MDD expects as the return value a DWORD value (ERROR_SUCCESS = 0
    for success), but the PDD-function (
    https://msdn.microsoft.com/en-us/library/dn197953.aspx) returns a BOOL (TRUE for success). That did not fit! When the PDD-part returns TRUE (=1) and want to report success, then this is for the MDD-part an error!

    Regards

    Markus

    Thursday, November 26, 2015 8:39 AM

Answers

  • I am confused, why is this a problem with the MDD and not your PDD?  The link that you provided says:

    Return Value

    Boolean value that indicates whether the function succeeded.

    I am not sure why you interpreted that as the PDD should return TRUE for success.

    The fact that the PDD returns a Boolean and it is interpreted as a DWORD isn't really a problem - not pretty, but it should work.

    I am sure that the documentation is incomplete. At the bottom of the page it asks if the page was helpful, select no, then provide a reason.  Your reason should be that the return value information is incomplete.



    Bruce Eitman (eMVP)
    Senior Engineer
    Bruce.Eitman AT Eurotech DOT com
    My BLOG http://geekswithblogs.net/bruceeitman
    I work for Eurotech

    Tuesday, December 1, 2015 2:15 PM
    Moderator

All replies

  • Thank you. Seems MS Embedded guys are very busy with Win10 IoT:)
    Friday, November 27, 2015 8:58 AM
  • I am confused, why is this a problem with the MDD and not your PDD?  The link that you provided says:

    Return Value

    Boolean value that indicates whether the function succeeded.

    I am not sure why you interpreted that as the PDD should return TRUE for success.

    The fact that the PDD returns a Boolean and it is interpreted as a DWORD isn't really a problem - not pretty, but it should work.

    I am sure that the documentation is incomplete. At the bottom of the page it asks if the page was helpful, select no, then provide a reason.  Your reason should be that the return value information is incomplete.



    Bruce Eitman (eMVP)
    Senior Engineer
    Bruce.Eitman AT Eurotech DOT com
    My BLOG http://geekswithblogs.net/bruceeitman
    I work for Eurotech

    Tuesday, December 1, 2015 2:15 PM
    Moderator