On Tue, Oct 28, 2014 at 12:19:04AM +0000, Mark Brown wrote:
On Fri, Oct 24, 2014 at 07:03:57PM -0700, Nicolin Chen wrote:
Kernel dump (WARN_ON) ocurred during system boot-up inside regmap_write():
------------[ cut here ]------------ WARNING: CPU: 0 PID: 47 at kernel/locking/lockdep.c:2744 lockdep_trace_alloc+0xe8/0x108()
Even though this may be a bug that should be fixed, I still try to send this patch as a quick fix (work around) since it does no harm to assign default values of every registers when using regcache.
It's not a bug, it's not reasonable to default allocations to atomic and we can't really tell what context we're in. Anything used inside a heavily locked path should either have a default provided or arrange for a prior write to set up the cache.
I've a little trouble to understand the prior write over here. Inside my probe() there's a register_init() call which has a set of regmap_write(). And then the first regmap_write() results the dump. Does that mean this regmap_write() isn't prior write? If so, how should I do if not setting default values here -- Some IPs may have default value 0 for registers. And this would make reg_defaults tedious since there's nothing special to assign.
And actually I remember I haven't seen any dump when I sent the initial patch for the whole ASRC driver but it manifested last month. I thought it might be a partially-merging issue and it would be fixed after merge window's done.....
Thank you Nicolin