User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0) Gecko/20100101 Firefox/4.0 Build Identifier: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0) Gecko/20100101 Firefox/4.0 My notebook is an Acer Aspire 5820TG with two graphic cards (Intel HD and ATI HD 5650 1GB), called "Hybrid Graphic". You can switch between these graphic cards to save power (Intel) or to use CAD applications (ATI). If you switch to ATI you get a black screen in the area, where the website is normally displayed. Both of the graphic drivers are up-to-date. I have no problems with Chrome, IE9, Opera or other applications. Reproducible: Always Steps to Reproduce: 1.Start Notebook with Intel HD graphic 2.Open Firefox 4.0 with e.g. "www.gmx.net" and "www.google.de" 3.Switch to ATI graphic 4.You see a black area instead of the website (if not press F5 or open a new tab) 5.if you start a "second" Firefox, you´ll see the same problem 6.You have to close all firefox.exe and start firefox again to solve the problem

Please post the graphic section from about:support

you can turn off hw acceleration in options menu, advanced section in the meantime.

(In reply to comment #2) > Please post the graphic section from about:support Okay, part 1: about:support using Intel chip -------------------------------------------------------------------------- Karten-Beschreibung Intel(R) HD Graphics Vendor-ID 8086 Geräte-ID 0046 Karten-Ram Unknown Karten-Treiber (driver) igdumd64 igd10umd64 igdumdx32 igd10umd32 Treiber-Version (driver version) 8.741.1.6000 Treiber-Datum (date of driver release) 10-21-2010 Direct2D aktiviert false DirectWrite aktiviert false (6.1.7600.16763, font cache n/a) WebGL-Renderer Google Inc. -- ANGLE -- OpenGL ES 2.0 (ANGLE 0.0.0.541 GPU-beschleunigte Fenster (GPU-acellerated windows) 1/1 Direct3D 9 ------------------------------------------------------------------------------- part 2 using ATI-graphic card: ---------------------------------------------------------------------------- Grafik Karten-Beschreibung ATI Mobility Radeon HD 5650 Vendor-ID 1002 Geräte-ID 68c1 Karten-Ram 1024 Karten-Treiber atiu9p64.dll atiuxp64 atiuxp64 atiu9pag atiuxpag atiuxpag atiumdva atiumd6a atitmm64 Treiber-Version 8.741.1.6000 Treiber-Datum 10-21-2010 Direct2D aktiviert false DirectWrite aktiviert false (6.1.7600.16763, font cache n/a) WebGL-Renderer Google Inc. -- ANGLE -- OpenGL ES 2.0 (ANGLE 0.0.0.541) GPU-beschleunigte Fenster 0/1

(In reply to comment #3) > you can turn off hw acceleration in options menu, advanced section in the > meantime. Thank you for this hint, it works!! Uncheck "Hardwarebeschleunigung verwenden, wenn verfügbar" (using hw acelleration, if available) solves the problem.

Hmm, That hybrid functionality is kinda of a new concept in the graphics space. Intel usually has a more worse experience with Firefox then ATI which is for the most part better, so this is interesting. cc'ing bas

I get the same problem with a similar notebook as Jan. If I switch back to Intel graphics, Firefox goes back to normal. It seems the graphics is somehow tied to the chip, and it goes black when the other chip is activated.

(In reply to Dennis "Dale" Y. [:cuz84d] from comment #6) > Hmm, That hybrid functionality is kinda of a new concept in the graphics > space. Intel usually has a more worse experience with Firefox then ATI > which is for the most part better, so this is interesting. > > cc'ing bas I would see it the other way round, having a laptop that is ~4 years old with switchable graphics. Utilizing GPU resources in Firefox is a new concept that is not well enough implemented - in Firefox. Switching off HW-accelleration significantly affects browsing speed and reduced Firefox to a 2nd generation browser. BTW for all that want to use the browser with HW-accelleration activated: Simply restart the browser - it will become aware of the current configuration and everything will work. However, when you switch back the same will happen (black regions). Considering this behavior it seems that the code is not aware of that a change of processing hardware can happen during operation and leaves the pointers in the memory space of the GPU it originally started with. Furthermore: does this only happen in MS-windows, or are other OSs affected as well?

The fact that the internal GPU-check of Firefox does not work is also seen if one tries about:support and looks at the GPU section after switching GPUs while leaving FF running. - Be aware that this only works when hw-acceleration is switched off (since the screen will not be updated due to the bug in accelerated mode)

Another way to address this issue is to block the ability to switch graphics if the program is running. This is how IE handles it. (badly IMHO)