Numonyx NOR flash mutex problem when creating UBI volumes

Michael Cashwell mboards at
Wed Feb 2 09:54:39 EST 2011

On Feb 2, 2011, at 6:18 AM, Stefan Bigler wrote:

> To find the problem I added few printk in the cfi_cmdset_0001.c
> Adding a printk for erase suspend make the problem show always.

Interestingly, I've tended to see the problem also when doing UBI, but during writes, not formatting. And in my case adding printks to any relevant hot path tended to make the problem vanish.

> I expect a problem with the protection as discussed already in the thread Numonyx NOR and chip->mutex bug?

I believe I've found the issue. It was not a mutex bug as I originally thought though it was true that not dropping the chip mutex while waiting for lengthy commands to complete did mask the problem.

I was going to post my results later today anyway but as you are also struggling I'll endeavor to do this soon. I will also make the post as a follow-on to the message thread I originally started.

Just a few minutes, please.

-Mike Cashwell

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