The code in gfxWindowsPlatform to handle the render-mode preference does not correctly check that the preference value is valid. This results in complete failure of rendering (blank windows) if the value is out of range. STR: use a current Minefield trunk build and set mozilla.widget.render-mode to 6, to experiment with Direct2D rendering. Quit Minefield, and launch Firefox 3.6 with the same profile. Windows will be completely blank, because Gecko 1.9.2 doesn't recognize render-mode 6. Looks like the problem is the use of || instead of && when checking that the value is in range.

Comment on attachment 429786 [details] [diff] [review] correctly check the validity of the render-mode value Indeed.

Pushed http://hg.mozilla.org/mozilla-central/rev/d093647cd0af

Comment on attachment 429786 [details] [diff] [review] correctly check the validity of the render-mode value Requesting approval for 1.9.2.2 - this is a simple bugfix with no risk, and may be critical to users who experiment with D2D using 3.7-alpha or trunk builds and then go back to running 3.6.

Comment on attachment 429786 [details] [diff] [review] correctly check the validity of the render-mode value a=beltzner for 1.9.2.2; jdrew tells me that without this, people who test Direct2D builds will be boned if they switch back to 1.9.2.2 or 1.9.1.9. Joe said he'd even check it in.

Comment on attachment 429786 [details] [diff] [review] correctly check the validity of the render-mode value This pref is not present on the 1.9.1 branch.

http://hg.mozilla.org/releases/mozilla-1.9.2/rev/550b0a052840 This should block 1.9.2.2, too.

verified FIXED using the steps to reproduce in comment 0 ... from build: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.3a4pre) Gecko/20100322 Minefield/3.7a4pre to Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.2) Gecko/20100316 Firefox/3.6.2