On Wed, 22 Aug 2007, [email protected] wrote:
>
> If you were running 2.6.26-rc3, that's quite possibly because you didn't
> have the follow-up patch that fixed my original patch... it wasn't in
> 2.6.26-rc3
Well, I was running "current git", and it's never been there. So not just
a -rc3 issue.
> That could definitely cause mouse lock-ups. Sorry, that should have
> occurred to me yesterday when you mentioned the problem your kids were
> seeing, but it didn't for some reason.
Btw, could it have caused the USB stack to be *really* confused? Some of
those mouse lockups ended up also locking the machine hard (ie no ping, no
nothing), and I'm a bit worried that there was something else going on
too..
That said, if you can actually re-create the MMF problems, could you
please try the patch that Arjan suggested? Ie add a
/*
* Some broadcom chips are buggy and can't take more than 5 usec as DMA
* latency; inform the rest of kernel of this.
*/
if (weird_broadcom_chip())
set_acceptable_latency("ehci", 5);
to the USB driver, and then add something like
static inline int cpufreq_acceptable_latency(struct cpufreq_policy *policy)
{
unsigned long latency;
/* Policy latency in usec */
latency = policy->cpuinfo.transition_latency / 1000;
if (latency > system_latency_constraint())
return -EINVAL;
return 0;
}
adn then add calls to this from both the "__cpufreq_set_policy()" function
and the "__cpufreq_driver_target()" one too..
That should disable cpufreq with that broken chip, which is perhaps a big
draconian, but it's certainly better than having the USB layer know about
cpufreq internals directly.
In the longer run, I think we can move the "system_latency_constraint()"
checking from the policy registration into each CPU frequency driver, so
that it could be more dynamically decide about "can we do it right _now_"
rather than globally saying "we can't do it with this hardware".
Linus
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