xdpyinfo(1)를 써서 DOUBLE_BUFFER extension이 지원되는지 먼저 살펴보세요.

--
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
Korean Ver: http://www.cinsk.org/cfaqs/

감사합니다.
해당 명령을 써보니 DOUBLE_BUFFER가 있네요

number of extensions:    33
    BIG-REQUESTS
    Composite
    DAMAGE
    DOUBLE-BUFFER                   <--- 더블버퍼
    DPMS
    Extended-Visual-Information
    GLX                             <--- GLX
    MIT-SCREEN-SAVER
    MIT-SHM
    MIT-SUNDRY-NONSTANDARD
    RANDR
    RECORD
    RENDER
    SECURITY
    SGI-GLX
    SHAPE
    SYNC
    TOG-CUP
    X-Resource
    XAccessControlExtension
    XC-APPGROUP
    XC-MISC
    XFIXES
    XFree86-Bigfont
    XFree86-DGA
    XFree86-DRI                <--- DRI?
    XFree86-Misc
    XFree86-VidModeExtension
    XINERAMA
    XInputExtension
    XKEYBOARD
    XTEST
    XVideo

이렇게 되어있습니다.
설정은 제대로 되어있는건가요?
/etc/X11/xorg.conf 에는

Section "Device"
        Identifier      "Configured Video Device"
EndSection

Section "Monitor"
        Identifier      "Configured Monitor"
EndSection

Section "Screen"
        Identifier      "Default Screen"
        Monitor         "Configured Monitor"
        Device          "Configured Video Device"
EndSection

이런식으로만 돼 있는데 설정을 더 해줘야할까요? 예를 들어 DRI 설정이라든가..
전 옛날식으로 xorg.conf에 모든 설정이 다 써있을 줄 알았는데 아니어서 손 놓고 있었습니다.

Xorg.log에는 "Will not try to enable page flipping" 이라는 부분이 있네요... 모니터가 1280x768해상도인데 1024x768로 쓰는 지금 설정이 문제가 있는 걸까요?

(II) intel(0): Output VGA using initial mode 1280x768
(II) intel(0): detected 256 kB GTT.
(II) intel(0): detected 7932 kB stolen memory.
(==) intel(0): video overlay key set to 0x101fe
(==) intel(0): Will not try to enable page flipping
(==) intel(0): Triple buffering disabled
...(생략)
(II) intel(0): [drm] installed DRM signal handler
(==) intel(0): VideoRam: 262144 KB
(**) intel(0): Framebuffer compression disabled
(**) intel(0): Tiling enabled
...(생략)
(WW) intel(0): EXA greedy migration mode enabled.
(II) EXA(0): Forcing greedy migration option
(II) EXA(0): Offscreen pixmap area of 31457280 bytes
(II) EXA(0): Driver registered support for the following operations:
(II)         Solid
(II)         Copy
(II)         Composite (RENDER acceleration)
...(생략)
(II) intel(0): DPMS enabled
(II) intel(0): Set up overlay video
(II) intel(0): direct rendering: Enabled
(--) RandR disabled
...(생략)
(WW) AIGLX: 3D driver claims to not support visual 0x23
(WW) AIGLX: 3D driver claims to not support visual 0x24
(WW) AIGLX: 3D driver claims to not support visual 0x25
(WW) AIGLX: 3D driver claims to not support visual 0x26
(WW) AIGLX: 3D driver claims to not support visual 0x27
(WW) AIGLX: 3D driver claims to not support visual 0x28
....
(WW) AIGLX: 3D driver claims to not support visual 0x31
(WW) AIGLX: 3D driver claims to not support visual 0x32
(II) AIGLX: Loaded and initialized /usr/lib/dri/i915_dri.so
(II) GLX: Initialized DRI GL provider for screen 0
(II) intel(0): Setting screen physical size to 338 x 203
...(생략)

이렇게 나오는군요
With lots of love..
Daniel Jiseok Song