Okay, now I'm actually getting angry. Looking in your published kernel sources, the SD driver s3c2440mci is
not source. There's a binary blob, meaning the kernel you have
published as "Source code" is anything but.
The vanilla kernel source, meanwhile, has a s3cmci driver which probably works better, so this offense is doing damage every which way you turn it! This driver has seen improvement since the 2.6.29.6 release used in the 903, so it's quite possible the bug I'm running into has already been fixed upstream.
Another possibility is that the bug is in silicon, in which case Samsung really owe us quite a bit more.
It looks like an
old issue has caused similar trouble.