SIGBUS on reading GPIO

I just got a new kernel build running, and the program (not the kernel) is dying attempting to read (not even write) a GPIO register (GPIO5, OE: 0x49056034)

Unhandled fault: external abort on non-linefetch (0x1018) at 0x4057a034

Bus error

I don't suppose anybody's seen this before?

I just got a new kernel build running, and the program (not the kernel) is
dying attempting to read (not even write) a GPIO register (GPIO5, OE: 0x49056034)

Unhandled fault: external abort on non-linefetch (0x1018) at 0x4057a034

That usually happens when you try to access registers of a block which has its clocks turned off.

regards,

Koen

Koen Kooi wrote:

Unhandled fault: external abort on non-linefetch (0x1018) at 0x4057a034

That usually happens when you try to access registers of a block which has its clocks turned off.

Enabling the clocks works, with one caveat: once the error has occurred, it continues to occur no matter what clocks you set, until you give up and reset the board. I only discovered this because I switched over to my older, working kernel to see what it's registers were.