Re: magnetic closure on case activates device
 

Nope never has - it seems to be too far or too weak to have any effect on the sensor.

Re: N900 sensitive to magnets. Magnetic case latches can wake device.
 

See https://bugs.maemo.org/show_bug.cgi?id=6689#c17 for a workaround.

Re: N900 sensitive to magnets. Magnetic case latches can wake device.
 

My case has 4 magnets on it. 2 on the case and 2 on the flap.

The only issue I have had is that occasionally, my sd card gets dismounted (easy to remount). Other than that the screen will flash on for a second when I pull it out, but goes right back off.

No issues with battery life. (It doesn't get stuck on in the case).

Case was a generic smart phone case from Best Buy, fits nicely, easy to slide out, <$20.

Re: N900 sensitive to magnets. Magnetic case latches can wake device.
 

Are you sure that SD card dismount is controlled by magnetic switch?

Reading multiple posts I assumed the same but today I found that SD mount/unmount is controlled by covering a small hole near camera lens under cover. If I cover this hole with finger or piece of black paper with open back cover my SD unmounts and mounts again after I remove a finger.

Re: N900 sensitive to magnets. Magnetic case latches can wake device.
 

All I can tell you is that without removing my cover (I even have a cheap "rubberized" plastic cover on the back) that my SD card occasionally disappears from the file manager. In the beginning, it would also occasionally report corrupted, but since I reformatted it, that hasn't happened.

I assumed that this was related to the magnets. If not, I can't imagine how else that would happen?

Now that I think about it, perhaps the plastic case is keeping it far enough away from the magnets? (as far as activating the screen)

Re: N900 sensitive to magnets. Magnetic case latches can wake device.
 

Same here. My SD card gets dismounted at times when my N900 is in the case. Other than that I don't have an issue.

Re: N900 sensitive to magnets. Magnetic case latches can wake device.
 

It was discovered that there are two hardware versions of N900 (at least it looks like - see https://bugs.maemo.org/show_bug.cgi?id=6689)

One is with magnetic switch for back cover, and another one (my, I am in California - direct buy from Nokia) has a small hole near camera lens with light sensor which monitors access to back-cover SD card. I was able to dismount SD card putting my finger over that hole.

Re: N900 sensitive to magnets. Magnetic case latches can wake device.
 

I thought the light sensor was used to detect the camera door position. There are white and black squares on the inside of the cover. Black for closed, white for open. When the cover is on, this triggers the camera.

Obviously, mine has the light sensor, but it has no impact on the sd card. As far as I think anyone knows, there are pre-production devices and production devices. There is only one style of the hardware for production devices. Otherwise you'd have to differtiate the firmware based on light sensor/magnetic sensor and we haven't seen that. Any time you opened the camera cover your card would unmount.

I'll bet while pressing on the light sensor, you stressed the sd card holder and the card contact briefly came away from the N900 contacts. Please check again carefully, and I bet the light sensor doesn't affect the card.

Re: N900 sensitive to magnets. Magnetic case latches can wake device.
 

OK, may be - I don't want to open cover again for now, it's pins are fragile.

But following advice in that bug report - and my KBD is not unlocked in my magnetic case anymore. It definitely should save me battery. Lightning screen and KBD sucks the power.

Re: N900 sensitive to magnets. Magnetic case latches can wake device.
 

A reliable way to test this is to run cat /sys/class/mmc_host/mmc0/cover_switch with the cover "on" and with the cover "off" (or magnet, or whatever you do).

Having had a look at the schematics and the kernel sources, it doesn't look like there's an easy (userspace-only) way to stop the SD-card from unmounting when the back cover comes off (or a magnet is waved near it).

It's possible to do with a kernel recompile, a simple kernel module, or some run-time patching, but I cannot find any knobs exposed to userspace to disable it.