Re: lockdep and threaded IRQs (was: ...)
From: David Brownell <hidden>
Date: 2009-03-03 02:37:28
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On Monday 02 March 2009, Ingo Molnar wrote:
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p.s. Note that those changes would still leave the lockdep bug around ... it will still be breaking various drivers that use normal IRQs, by forcibly enabling IRQF_DISABLED.it's not a bug - and i think Peter explained that already.
No. But I did get a non-response that didn't include any explanation, and relied totally on unfounded assertions combined with the presumption that someday IRQF_DISABLED will be forced on in all drivers.
It's not really breaking things either - we've had this for more than 2 years.
I happened across two MMC host adapter drivers which it broke. They preceded the patch whereby lockdep changes request_irq() semantics. The drivers break only with lockdep ... so platforms relying on those can't use lockdep. No reason to think there aren't more such bugs lurking. We also wasted quite a few months tracking down USB bugs that were masked by that patch ... the indeterminacy of IRQF_DISABLED behavior given IRQF_SHARED was hidden by enabling lockdep. Led to a lot of totally crapulous oops traces, I assure you. So ... it has most certainly broken things. There has seemed to be a bit of stick-fingers-in-ears going on, that prevents hearing about such problems though. - Dave -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html