I am using xscreensaver to lock my screen. Additionally to that, my monitor goes to standby , i.e turn display off, after 30 minutes of inactivity.It has happened to me twice now, that I have locked my screen, using  xscreensaver-command --lock and when I came back after few hours and moved my mouse, the monitor came back from standby but instead of the expected xscreensaver login window, I was dropped directly into my desktop session - without having to authenticate.I don't know whether there is any correlation with the power management feature, but it did not happen to me before when I was not using automatic monitor suspend.Also, I don't have any .Xauthority file in my home, but again not sure whether that is relevant.I am using Debian Wheezy and LXDECan somebody please suggest how to investigate this problem ?$ xdpyinfoname of display:    :0.0version number:    11.0vendor string:    The X.Org Foundationvendor release number:    11204000X.Org version: 1.12.4maximum request size:  16777212 bytesmotion buffer size:  256bitmap unit, bit order, padding:    32, LSBFirst, 32image byte order:    LSBFirstnumber of supported pixmap formats:    7supported pixmap formats:    depth 1, bits_per_pixel 1, scanline_pad 32    depth 4, bits_per_pixel 8, scanline_pad 32    depth 8, bits_per_pixel 8, scanline_pad 32    depth 15, bits_per_pixel 16, scanline_pad 32    depth 16, bits_per_pixel 16, scanline_pad 32    depth 24, bits_per_pixel 32, scanline_pad 32    depth 32, bits_per_pixel 32, scanline_pad 32keycode range:    minimum 8, maximum 255focus:  window 0x1e00004, revert to Parentnumber of extensions:    26    BIG-REQUESTS    Composite    DAMAGE    DOUBLE-BUFFER    DPMS    DRI2    Generic Event Extension    MIT-SCREEN-SAVER    MIT-SHM    RANDR    RECORD    RENDER    SECURITY    SHAPE    SYNC    X-Resource    XC-MISC    XFIXES    XFree86-DGA    XFree86-VidModeExtension    XINERAMA    XInputExtension    XKEYBOARD    XTEST    XVideo    XVideo-MotionCompensationdefault screen number:    0number of screens:    1screen #0:  dimensions:    1920x1080 pixels (508x285 millimeters)  resolution:    96x96 dots per inch  depths (7):    24, 1, 4, 8, 15, 16, 32  root window id:    0x6f  depth of root window:    24 planes  number of colormaps:    minimum 1, maximum 1  default colormap:    0x20  default number of colormap cells:    256  preallocated pixels:    black 0, white 16777215  options:    backing-store NO, save-unders NO  largest cursor:    64x64  current input event mask:    0x7a003c    ButtonPressMask          ButtonReleaseMask        EnterWindowMask              LeaveWindowMask          StructureNotifyMask      SubstructureNotifyMask       SubstructureRedirectMask FocusChangeMask          PropertyChangeMask         number of visuals:    3  default visual id:  0x21  visual:    visual id:    0x21    class:    TrueColor    depth:    24 planes    available colormap entries:    256 per subfield    red, green, blue masks:    0xff0000, 0xff00, 0xff    significant bits in color specification:    8 bits  visual:    visual id:    0x22    class:    DirectColor    depth:    24 planes    available colormap entries:    256 per subfield    red, green, blue masks:    0xff0000, 0xff00, 0xff    significant bits in color specification:    8 bits  visual:    visual id:    0x6d    class:    TrueColor    depth:    32 planes    available colormap entries:    256 per subfield    red, green, blue masks:    0xff0000, 0xff00, 0xff    significant bits in color specification:    8 bits
xscreensaver sometimes unlocks locked screen automatically, after returning from monitor standby mode
login;authentication;power management;xscreensaver
I would definitely say this sounds like a bug. My suggestion, if you're going to use xscreensaver allow it to handle power management. At the command line type xscreensaver-demo, and in the GUI go to the Advanced tab and make sure 'Power Management Enabled' is checked (also tweak the settings how you'd like them to be).As well, start xscreensaver from the command-line with xscreensaver -log ~/xscreensaver.log and see what the log says when this happens.