How to diagnose a graphic looking bug? I got the following strange image on both low corners of 2 application windows:


Firefox (22)
Preview (MacOS X)




This strange image is following the windows corners when I move them.
This is occuring on a MacBookPro6,2 (mid 2010), running MacOS X 10.6.8 fully updated.
This image can be captured (cmd ⌘+shift ⇧+4).

Context

The mother board and video card were replaced by an Apple Store.

Since I got it back 3 days ago, this MBP has been up and running and heavily tested. It went through many graphical use without a problem during 3 full days.

This event happened a few minutes after an exit from hybernation
where the battery was totally exhausted.

Graphic cards:


Intel HD Graphics: rev 0x0018
NVIDIA GeForce GT 330M: rev 0x00a2


This problem occured arround 08:20. Here the nearby content of /var/log/kernel.log:


Aug  6 22:48:49 my__MBP kernel[0]: AirPort: Link Up on en1
Aug  6 22:49:26 my__MBP kernel[0]: en1: 802.11d country code set to 'FR'.
Aug  6 22:49:26 my__MBP kernel[0]: en1: Supported channels 1 2 3 4 5 6 7 8 9 10 11 12 13 36 40 44 48 52 56 60 64 100 104 108 112 116 120 124 128 132 136 140
Aug  6 23:03:31 my__MBP kernel[0]: hfs: Initializing the journal (joffset 0x3000 sz 0x80000)...
Aug  7 08:00:13 my__MBP kernel[0]: hibernate image path: /var/vm/sleepimage
Aug  7 08:00:13 my__MBP kernel[0]: sizeof(IOHibernateImageHeader) == 512
Aug  7 08:00:13 my__MBP kernel[0]: Opened file /var/vm/sleepimage, size 4294967296, partition base 0xc805000, maxio 400000 ssd 0
Aug  7 08:00:13 my__MBP kernel[0]: hibernate image major 14, minor 2, blocksize 512, pollers 5
Aug  7 08:00:13 my__MBP kernel[0]: hibernate_alloc_pages flags 00000000, gobbling 0 pages
Aug  7 08:00:13 my__MBP kernel[0]: hibernate_setup(0) took 0 ms
Aug  7 08:00:13 my__MBP kernel[0]: AirPort: Link Down on en1. Reason 8 (Disassociated because station leaving).
Aug  7 08:00:13 my__MBP kernel[0]: System SafeSleep
Aug  7 08:19:17 my__MBP kernel[0]: hibernate_page_list_setall start 0x450cb000, 0x450ea000
Aug  7 08:19:17 my__MBP kernel[0]: hibernate_page_list_setall time: 397 ms
Aug  7 08:19:17 my__MBP kernel[0]: pages 988881, wire 137387, act 328832, inact 12950, spec 0, zf 9189, throt 0, could discard act 130843 inact 255304 purgeable 25377 spec 88999
Aug  7 08:19:17 my__MBP kernel[0]: hibernate_page_list_setall found pageCount 488358
Aug  7 08:19:17 my__MBP kernel[0]: IOHibernatePollerOpen, ml_get_interrupts_enabled 0
Aug  7 08:19:17 my__MBP kernel[0]: IOHibernatePollerOpen(0)
Aug  7 08:19:17 my__MBP kernel[0]: writing 486856 pages
Aug  7 08:19:17 my__MBP kernel[0]: encryptStart 541a70
Aug  7 08:19:17 my__MBP kernel[0]: encryptEnd 4e56560
Aug  7 08:19:17 my__MBP kernel[0]: hibernate_machine_init: state 2, image pages 137257, sum was 7d2d0110, image1Size 9911400, conflictCount 403, nextFree 996
Aug  7 08:19:17 my__MBP kernel[0]: hibernate_page_list_discard time: 265 ms, discarded act 130843 inact 255304 purgeable 25377 spec 88999
Aug  7 08:19:17 my__MBP kernel[0]: IOHibernatePollerOpen(), ml_get_interrupts_enabled 0
Aug  7 08:19:17 my__MBP kernel[0]: IOHibernatePollerOpen(0)
Aug  7 08:19:17 my__MBP kernel[0]: hibernate_machine_init reading
Aug  7 08:19:17 my__MBP kernel[0]: PMStats: Hibernate read took 9038 ms
Aug  7 08:19:17 my__MBP kernel[0]: hibernate_machine_init pagesDone 488202 sum2 c5a58d42, time: 9038 ms
Aug  7 08:19:17 my__MBP kernel[0]: Wake reason =
Aug  7 08:19:17 my__MBP kernel[0]: System SafeSleep Wake
Aug  7 08:19:17 my__MBP kernel[0]: Previous Sleep Cause: -60
Aug  7 08:19:17 my__MBP kernel[0]: Previous Shutdown Cause: -60
Aug  7 08:19:17 my__MBP kernel[0]: com_apple_driver_AppleUSBCardReaderUMC:: Stop::Controller Reset
Aug  7 08:19:17 my__MBP kernel[0]: en1: 802.11d country code set to 'X3'.
Aug  7 08:19:17 my__MBP kernel[0]: en1: Supported channels 1 2 3 4 5 6 7 8 9 10 11 12 13 36 40 44 48 52 56 60 64 100 104 108 112 116 132 136 140
Aug  7 08:19:17 my__MBP kernel[0]: USBMSC Identifier (non-unique): 000000009833 0x5ac 0x8403 0x9833
Looks like an issue with GPU drivers. I have such issues on other machines with other versions of OSX time to time. Most of them are likely addressed in next versions of OSX.

I would start with checking Console.app. Various subsystem might log some useful information.