lkml.org 
[lkml]   [2007]   [Oct]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [Linux-usb-users] OHCI root_port_reset() deadly loop...
> Bad news, even with the rwsem after a lot more testing I can still
> trigger the hang in ohci_hub_control() :-(
>
> I think we need to go back to considering the total serialization
> approach to this problem.

We shouldn't need that. What happens if you add an msleep(5)
before ehci-hcd::ehci_run() drops ehci_cf_port_reset_rwsem?

The theory there being that the switch triggered by setting CF
doesn't take effect instantaneously, contrary to the effective
assumption of that code. A delay of 5 msec seems like it should
be more than enough, but that's kind of a guess ... it's good to
keep that low, since unfortunately that's in the critical path
for OLPC "resume from idle".

- Dave

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-10-16 01:41    [W:1.697 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site