Comment 12 for bug 386907

Seems the patch went in upstream post 2.6.31. As an interim solution you can try running one of the latest mainline kernel builds which should contains this patch - For ex http://kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.32-rc4/

ogasawara@yoji:~/linux-2.6$ git show e87b2c42b397ae64ac13a390011931f7ef222321

commit e87b2c42b397ae64ac13a390011931f7ef222321

Author: Jesse Barnes <email address hidden>

Date: Thu Sep 17 18:14:41 2009 -0700

    drm: fix drm_fb_helper handling of kernel crtcs