On Wed, Nov 10, 2010 at 02:43:31PM -0600, Jason Wessel wrote:
> On 11/10/2010 02:27 PM, Dmitry Torokhov wrote:
> > On Wednesday, November 10, 2010 12:13:20 pm Jason Wessel wrote:
> >> On 11/09/2010 01:34 AM, Dmitry Torokhov wrote:
> >>> Now that KGDB knows how to release keys that have been pressed when
> >>> entering the debugger the only issue left is that SysRq handler is too
> >>> greedy and always swallows Alt+SysRq, causing print screen hotkey to
> >>> stop working. The solution is to re-inject the key combo when user
> >>> releases SysRq without pressing any other keys. The patch below does
> >>> just that and also releases keys that have been pressed before we enter
> >>> SysRq mode.
> >>>
> >>> Note that it depends on a patch to input core that will stop events
> >>> injected by one input handler from reaching the very same input handler
> >>> (attached).
> >>>
> >>> Comments/testing/suggestion are sought after.
> >> I applied both patches and tested all the known failures cases I had on
> >> my list and it looks good, for the non kdb cases.
> >>
> >> Tested-by: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
> >>
>
> >> However... I also tested this with the kdb keyboard release
> >> patches plus your latest 2 patches and we appear to have an
> >> incompatibility. The behavior is that when exiting kdb the print
> >> screen trigger fires. I had not had a chance to debug it as of
> >> yet.
> >>
> >
> > Hmm, let me think...
> >
>
> So I debugged it. The key up events are peeled off in linear order
> with the kdb release key code.
>
> The sequence looks like this
>
> down - alt
> down - printScr
> down - g <-- Enters kdb
>
> The kdb release code simulates the events
> up - g
> up - alt
> up - printScr
>
> That tells me we have something bad about the key events going on, or
> that we care about release ordering in the release handler.
>
Ah, I see. I bet the shortcut for print screen is actually triggered on
_release_ and X drivers do not filter release events for which they have
not seen presses. Oh well...
Coudl you try sticking somethgin like this into sysrq code?
case KEY_SYSRQ:
if (value == 1 ... ) {
....
}
if (sysrq->active)
clear_bit(KEY_SYSRQ, handle->dev->key);
This is a bit dirty but sysrq is pretty special anyways...
Thanks.
--
Dmitry
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