i have already sent my phone to nokia 3 times so far and everytime i get it back all they do is reflash the firmware on it. and still the problem persists. it is all find inside the building with any kind of lights on but while i am out-side in a sunlight, and on the phone my phone thinks that there is something infront of the proximity sensor. even a shadow cast over the proximity sensor will make the screen go blank also if the sensor is directly facing sunlight it acts the same way. i really want to get this fixed now without sending it back now, its been a month and half it has been going back and forth, feels like nokia repair has had my phone longer than myself now.
thanks

Did you have a screen protector?
Cut it in the proximity sensor part
I used to have this problem, but not anymore

no i donot have any screen protector,

bump bumppppppp

Could you maybe ... like... post a closeup picture of your proximity sensor in bright light that does not reflect on the surface? So one can look inside the "hole" of the sensor? Clean the surface first please.

This is a known problem:
https://bugs.maemo.org/show_bug.cgi?id=7772
There is no fix! and never will be! Sorry.

I had this problem, but only with a screen protector on, cutting a hole with a hole punch in the protector fixed it for me, but that isn’t going to help you!

The way to get around it, is to flick the lock slider, this will unlock the screen, as pressing the power button doesn’t do anything!

As you have this problem without a screen protector on, yours I'm afraid, is one of the worst. You will have to live with it, unless you can persuade Nokia to change your device.

Sorry I cannot be of any help.

Ok now, wait...

As a matter of fact, the proximity sensor works by emitting pulsing light and a photocell measuring if this pulsing light is "seen".
This will only be the case if something is directly over the sensor or near it.
You can test this by holding your n900 in front of a video recording device such as your webcam in darkness, and you will see this light.
If you do not see this light, the emitting diode is faulty and any light flicker will be interpreted as "something is in front of me"

Second guess is this one here, some program interfering with your calls / sensor readings: https://bugs.maemo.org/show_bug.cgi?id=7772#c67
Try if it works after flashing both firmware and emmc (!) and NOT restoring any of your programs.

Third guess would be : kernel stepping
Calling is somewhat a ressource hog. If you start calling, the CPU will lock to a certain frequency (forgot which one). This may interfere with the sensor timing, as the emitting diode flickers at a low rate. So the noise analysing algorithm, which should keep the ambient light off the readings can not certainly differ which one is noise.

Fourth guess. Your photocell isn't worthy of it's name, because there are fluctuations in the manufacturing process.

For first and fourth guess: these are hardware issues, try to insist at a Nokia Care Centre to swap your proximity sensor. Show them your receipts about the previous repair tries from nokia service and show them the problem personally.

Try second guess first (reflashing without restoring backup).


As a workaround: Open the keyboard, this should put the phone to landscape mode and you will see who is calling you (though annoying).

PS: cat /sys/devices/platform/gpio-switch/proximity/state in a terminal will give you the status of your sensor. Closed means something is in front.

well I called Nokia and they want me to send my phone back to them again, this is actually a 3rd replacement from them with the same problem. But the phone I had first never had this problem, but I had to send it for faulty display and every phone I got from them as a replacement had this problem.
They also have already sent me the shipping label but if this is a bug which might be fixed I might not send it.

Well after going through every comment on the bugzilla, I decided that I would not add my situation because there were two guys with the same problem and even with the syslog (Nokia) said that they WONT FIX because of the hardware limitation.
I guess now the only way to get this fixed is to send my phone back to the m()rons in Alabama for 4th time with same comments about proximity sensor does not work in sunlight, even a shadow makes proximity sensor to think it has been blocked.
This time a rep. from Nokia told me to put
ATTENTION: Quality Manager.
at the top will see if this will be fixed after the 4th time.