Can't detect external monitor, shows only 640x480

Question

Hi,
I'm using a Macbook Pro Unibody 13" 2.53GHz to connect to a Dell 2408WFP external monitor. It worked FLAWLESSLY with my old Macbook Pro using a DVI cable.
1) I first bought the infamous mini-Displayport to DVI adaptor. It didn't work (red static etc. check the page of this product on Apple's store website : you'll see it's a known issue). Cost me 35$
2) I then bought a mini-Displayport to Displayport cable. Thought it should work perfectly. It DOES NOT. The Macbook is apparently UNABLE TO DETECT my Dell and gives it a default resolution of 640x480. Which is ridiculous knowing that the Dell 2408WFP is capable of displaying 1900x1200.
It's really a pain. Does anyone know about this problem or have an idea how to solve it?
Thanks,
P.

Answer 1

Ok,
It was neither the cable nor the computer (thanks Apple). It was the monitor's EDID profile. Dell's problem.
There's two ways to fix this. 1) It is possible (I did it) to create a custom profile using SwitchResX. You'll need to hook up your computer to the monitor using a working connexion (I used DVI) and then use the "export" function in SwitchResX. It will give you a text file. In it you'll have enough data to fill SwitchResX' form to setup a custom profile. You'll then need to restart the computer, hook it with the Displayport cable and try to use this custom EDID profile. It worked for me.
For example (and hoping it will help others) here are the data you need to setup a custom profile for the Dell 2408WFP :
Descriptor #0 - Timing definition:
Mode = 1920 x 1200 @ 59,950Hz
Pixel Clock............. 154,00 MHz Non-Interlaced
Horizontal Vertical
Active.................. 1920 pixels 1200 lines
Front Porch............. 48 pixels 3 lines
Sync Width.............. 32 pixels 6 lines
Back Porch.............. 80 pixels 26 lines
Blanking................ 160 pixels 35 lines
Total................... 2080 pixels 1235 lines
Scan Rate............... 74,038 kHz 59,950 Hz
Image Size.............. 519 mm 324 mm
Border.................. 0 pixels 0 lines
Sync: Digital separate with
* Negative vertical polarity
* Positive horizontal polarity
2) Of course, you can call Dell and tell them about it. They are sending me a THIRD replacement monitor for this. Be prepared when you call them : I spoke with two representative (and among them a "senior technician") who DIDN'T know what was a Displayport. They even tried to sell me the idea that 640x480 is the native resolution for Displayport. It was hilarious. Really. I got them to look it up on Wikipedia.
Case solved. Apple 1 - Dell 0.
P.