4 Nov
2010
4 Nov
'10
2:43 p.m.
On Thu, Nov 04, 2010 at 10:16:45AM +0200, Peter Ujfalusi wrote:
The exisiting card->mutex can not be used for this purpose, since it has been taken in probe time in the snd_soc_instantiate_card function. Through probe calls from this function eventually dapm_power_widgets will be called, which will lead to dead lock.
Hrm. You're right that the card mutex has issues here but just adding a lock here leaves us with a race - whenever we make a change to widget power we're doing a read/modify/write cycle and those aren't locked at all. I'm not sure if we need a lower level lock to fix that, or a higher level lock which would make this one redundant but we ought to think about it and make sure we've picked the right way.