lkml.org 
[lkml]   [2008]   [Aug]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: INFO: possible recursive locking detected ps2_command
    On Fri, Aug 08, 2008 at 12:49:49PM +0200, Peter Zijlstra wrote:
    > On Thu, 2008-07-31 at 23:04 -0400, Dmitry Torokhov wrote:
    > > On Thu, Jul 31, 2008 at 02:57:39PM -0700, Andrew Morton wrote:
    > > >
    > > > (cc linux-input)
    > > >
    > > > On Thu, 31 Jul 2008 11:41:25 +0200
    > > > "Zdenek Kabelac" <zdenek.kabelac@gmail.com> wrote:
    > > >
    > > > > Hi
    > > > >
    > > > > During mouse unplugging from psaux connector from the laptops' docking
    > > > > station I've got attached INFO trace.
    > > > > (laptops still has synaptics device)
    > > > >
    > >
    > > Dell?
    > >
    > > > > Also for unknown reason to me psaux mouse & synaptic device do not
    > > > > work somehow together - is it hw limitation
    > > > > of /dev/input/mice interface?
    > > > > (USB mouse and synaptics do work quite well together)
    > > > >
    > > > > [ INFO: possible recursive locking detected ]
    > > > > 2.6.27-rc1 #48
    > > >
    > > > (it's 2.6.27-rc1)
    > > >
    > >
    > > Peter, here is the trace we talked about long time ago. For some reason
    > > lockdep annotation only works once. If reconnect is forced or psmouse
    > > module is reloaded lockdep starts complaining about passthrough port.
    >
    > Bit puzzling - and I don't have any ps2 hardware around to test with
    > (nor do I normally use modules - but that is fixable of course).
    >
    > Does Rabin's patch help?
    >
    > http://lkml.org/lkml/2008/8/7/329
    >

    I doubt it resolves problem fully because it only takes care of module
    unload. I can easily trip lockdep by reconnecting the device. Just to
    give some more details about the problem:

    - synaptics touchpads have a pass-through port that allows to connect
    either external mouse or maybe a trackpoint device. Both devices
    are represented by 'serio' structures and are handled by the same
    driver (psmouse).

    - as far as I know we have proper locking there and lockdep
    annotatinos were added to lockdep to reflect the nesting of the
    serio ports.

    - if child port (pass-through port) is destroyed and recreated (due
    to module unload, or because user requested reconnect through sysfs
    or system-initiated reconnect) lockdep starts complaining although
    the new child port should still have the same "depth" as the old
    one.

    Thanks!

    --
    Dmitry


    \
     
     \ /
      Last update: 2008-08-08 14:47    [W:2.363 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site