I wanted to be able to try out the new release of MESA 10.4 but only have Linux Mint 13 (based on Ubuntu 12.04 LTS). As such, I have added Pali's PPA to my software sources and installed MESA accordingly (the version available there is currently 10.5.0-git201412182300.e06b077~ubuntu12.04.1). I had assumed that it would contain the bug fixes described on the MESA 10.4 Release Notes (http://www.mesa3d.org/relnotes/10.4.html). Another positive benefit from performing this installation is that I have retained direct hardware rendering on my chipset without it falling back to software-rendering, which I recall being very sluggish.
Long story short, there are 3 main issues that concern my hardware and software mix:
1) windows showing incorrect drop shadows using the Cinnamon desktop environment
2) missing/incorrect background color for the panel menus while using the Cinnamon desktop environment
3) glx-dock (aka cairo-dock) showing an annoying white rectangle, each time the dock is hidden and re-drawn.
After having installed MESA 10.5(git), the only bug of the above 3 that appears to be resolve is the one pertaining to the incorrect drop shadows while using Cinnamon.......... the drop shadows for all windows are now the correct color.
However, the last two bugs persist.
Please refer to bugs #80050 and #72819 for more info.