HD4000 graphics problems when using a very big external screen
Hello,
I just got a new LG 34UM95 (3440x1440) which can get connected via Thunderbolt or DVI. Screen detection and activation is working fine.
However the screen is corrupted when moving the mouse or activating the dock animation or scrolling a window, ...
Scenario:
- MacBook Pro Mid 2012 (Intel HD4000),
- MacOS X 10.9.3
- really big external display (3440x1440) connected via Thunderbolt or DVI
- both displays (integrated end external display) active at same time
Problem:
- graphic errors (framebuffer corruptions) on both screens ==> it looks like the framebuffer memory size or some DMA transfer addresses are miscalculated
- when scaling down the external resolution to something smaller (e.g. 2560x1080) everything is working fine
- when closing the MacBook and using the external display only the big screen works flawlessly
==> Could you please have a look at this and fix the framebuffer corruption?
==> This might also be a race condition where the HD4000 driver accesses RAM which it should not have access to and could lead to an security attack.
Thanks,
Maik
MacBook Pro, OS X Mavericks (10.9.3)