Created attachment 84412 [details]
dmesg log

Ubuntu 13.04 64-bit (affects both x86 and x86_64)
Kernel - from nouveau/linux-2.6 repo - HEAD is
3b56bba6abaa70d629fccdcf8490e087ea3a1ab4
X.Org X Server 1.13.4
Mesa version e6013e4bee7ebff6b7bd2f3b95eb16e8949e228c
Family: NVC0
Chipset: GF116 (NVCF) (GTX 550 Ti)

Some elements are only rendered in top-left area of the window (screenshot to
be included). This affects both Portal and Team Fortress 2.

I've done a bisection and this is the result:

2149ce41ed6b10f7bff65d7b3f23fd03b89753e3 is the first bad commit
commit 2149ce41ed6b10f7bff65d7b3f23fd03b89753e3
Author: Christoph Bumiller <e0425955@student.tuwien.ac.at>
Date:   Sun Sep 30 22:59:34 2012 +0200

    nv50,nvc0: fix 3d engine blit for nvc0

:040000 040000 e0f165f869fed658f574a2719d0e841dda95139e
013265106fe6e2f2dab6b20811566fa5ba1106f3 M    src

There is nothing related to this issue in dmesg, but I'll include it anyway.