Created attachment 25102 [details]
xorg-core-dump.txt

Created attachment 25103 [details]
dmesg.log

dmesg after some crashes and then it works

What's the previous version working for you?

I *was* 2.6.99.902 but since I updated this and libdrm, I downgraded (I had a binary backup) and I can't find how come it won't work anymore. I'm still investigating.

Created attachment 25138 [details]
xorg.conf

I also updated my Xorg.conf but I'm sure I reverted all my changes.

I can repeat the following backtrace, I have 4 of those core dump, always after resuming from suspend.

MobileCPU / # file core.12879 
core.12879: ELF 32-bit LSB core file Intel 80386, version 1 (SYSV), SVR4-style, from '/usr/bin/X -br -deferglyphs 16 -auth /var/run/slim.auth vt07'

#0  0xffffe424 in __kernel_vsyscall ()
No symbol table info available.
#1  0xb7c6e09a in raise () from /lib/libc.so.6
No symbol table info available.
#2  0xb7c6f678 in abort () from /lib/libc.so.6
No symbol table info available.
#3  0xb7c6731c in __assert_fail () from /lib/libc.so.6
No symbol table info available.
#4  0xb7b91f07 in i830_lvds_mode_valid (output=0xad14098, pMode=0xbf8bca28) at i830_lvds.c:597
    pScrn = (ScrnInfoPtr) 0xb7bc7ff4
    pI830 = (I830Ptr) 0x54f00006
    pFixedMode = (DisplayModePtr) 0x81e64d8
#5  0xb7b931b8 in i830_lvds_create_resources (output=0xad14098) at i830_lvds.c:1158
    pScrn = (ScrnInfoPtr) 0x81e64d8
    pI830 = (I830Ptr) 0x1200
    intel_output = (I830OutputPrivatePtr) 0x1200
    dev_priv = (struct i830_lvds_priv *) 0x1200
    backlight_range = {181485720, -1081357784}
    data = -1212599880
    err = 4608
    i = -1212383244
#6  0xb7ba4671 in i830_sdvo_get_mode_from_dtd (mode=0xad14098, dtd=0xad14098) at i830_sdvo.c:743
No locals.
#7  0xb7b4fa3a in fbCopyRegion () from /usr/lib/xorg/modules//libfb.so
No symbol table info available.
#8  0xb7ba4123 in i830_sdvo_set_timing (output=0xad26948, cmd=252 'ü', dtd=0xadfe2b8) at i830_sdvo.c:586
    status = 255 'ÿ'
...
#13 No symbols table info available.

Adjusting severity: crashes & hangs should be marked critical.

This is a pretty weird crash... are you sure your X and xf86-video-intel packages match up, ABI-wise?  Btw, 2.6.30-rc has a lot of fixes over 2.6.29, so you might want to try it anyway.

I will give 2.6.30 a try before continuing with this bug then, I'll have to wait for final, I don't have that much time lately.
However I must add I recompiled my whole system 3 weeks ago, and I mean recompile with all the same version to be sure everything matches and the crash still appears.

Here is another backtrace I got, I don't know if it's the same, I found it in my / but don't have any log associated.

Core was generated by `/usr/bin/X -br -deferglyphs 16 -auth /var/run/slim.auth vt07'.
---Type <return> to continue, or q <return> to quit---q
Quit
(gdb) bt full
#0  0xffffe424 in __kernel_vsyscall ()
No symbol table info available.
#1  0xb7bf509a in raise () from /lib/libc.so.6
No symbol table info available.
#2  0xb7bf6678 in abort () from /lib/libc.so.6
No symbol table info available.
#3  0xb7bee31c in __assert_fail () from /lib/libc.so.6
No symbol table info available.
#4  0xb7b0644d in intel_batch_emit_dword (pI830=0x81e6628, dword=1425014790)
    at i830_batchbuffer.h:78
	__PRETTY_FUNCTION__ = "intel_batch_emit_dword"
#5  0xb7b069f9 in I830EXACopy (pDstPixmap=0xb760558, src_x1=1025, src_y1=0, 
    dst_x1=998, dst_y1=0, w=115, h=32) at i830_exa.c:387
	pScrn = (ScrnInfoPtr) 0x81cefe8
	pI830 = (I830Ptr) 0x81e6628
	cmd = 1425014790
	dst_x2 = 1113
	dst_y2 = 32
	dst_pitch = 4608
	src_pitch = 4608
	__FUNCTION__ = "I830EXACopy"
	__PRETTY_FUNCTION__ = "I830EXACopy"
#6  0xb7b22c49 in uxa_copy_n_to_n (pSrcDrawable=0xb760558, 
---Type <return> to continue, or q <return> to quit---
    pDstDrawable=0xb760558, pGC=0x0, pbox=0xbf94247c, nbox=0, dx=27, dy=0, 
    reverse=0, upsidedown=0, bitplane=0, closure=0x0) at uxa-accel.c:459
	screen = (ScreenPtr) 0x81ea668
	uxa_screen = (uxa_screen_t *) 0x81eb428
	src_off_x = 0
	src_off_y = 0
	dst_off_x = 0
	dst_off_y = 0
	pSrcPixmap = (PixmapPtr) 0xb760558
	pDstPixmap = (PixmapPtr) 0xb760558
	__FUNCTION__ = "uxa_copy_n_to_n"
#7  0xb7aa2a3a in fbCopyRegion () from /usr/lib/xorg/modules//libfb.so
No symbol table info available.
#8  0xb7b242ff in uxa_copy_window (pWin=0xac1c438, ptOldOrg={x = 1134, y = 0}, 
    prgnSrc=0xbd88cc8) at uxa-accel.c:844
	rgnDst = {extents = {x1 = 998, y1 = 0, x2 = 1113, y2 = 32}, data = 0x0}
	dx = 27
	dy = 0
	pPixmap = (PixmapPtr) 0xb760558
...
#13 0x00000000 in ?? () No symbol table info available.
(gdb) 

OK, that first backtrace looks like your stack was just smashed.  The second one is what we pushed a fix for tracking #21468.

commit e54a23bff068416ccbdb75d538dc7dcd40a6c95c
Author: Keith Packard <keithp@keithp.com>
Date:   Thu May 7 16:35:19 2009 -0700

    Fallback when VT inactive

*** This bug has been marked as a duplicate of bug 21468 ***