Re: "berzerko mouse"

Joe (josepha48@yahoo.com)
Mon, 9 Aug 1999 06:04:40 -0700 (PDT)

> >I didn't pay much attention to the recent thread about mice
> getting out of
> >sync on the 2.2 kernel because of ACKs not getting flushed
> from the input
> >buffer.
> >
> >But I noticed a thread about 'berzerko mouse' on the Linux
> kernel mailing list
> >which I thought might be relevant.
> >
> >However, that problem also appears to affect serial mice, and
> I thought the
> >ACK problem was only with PS/2 mice.
>
> Yes, the ACK problem is only relevant to the PS/2 mouse,
> because a) we
> don't send commands to, and expect reply from most serial mice
> we are
> dealing with, and b) XF86InputFlush() (which is actually a
> wrapper
> around tcflush()) should work correctly with the serial port.
>
> >Either way, it's more likely to be an X problem than a kernel
> problem, so I
> >suppose it ought to be brought up here.
>
> I doubt this is a server problem for the reasons I wrote
> above. And
> also c), the ACK or buffer flush problem exist only when the
> mouse is
> being initialized; it means that you see the problem as soon
> as you
> start the X server. If you experience some wired mouse
> behavior
> sometime after you use the mouse without a problem in the X
> session,
> it is definitely not related to the buffer flush problem
> discussed
> here.
>
> Besides, the XF86 mouse code has barely changed between 3.3.2
> and
> 3.3.4. If the serial mouse is now behaving erratically, its
> cause
> should be somewhere else. For example, isn't there a
> possibility that
> the serial port driver is dropping data from the serial mouse?
>

if the serial code has not changed in X since 3.3.2 to 3.3.4
then it is possible that the kernel is corrupting the buffer
data and then sending it to X corrupted..

> Kazu
>
> >If you respond to this message, please make sure that you
> include
> >joeja@mindspring.com in the Cc, because he's not on the devel
> mailing list.
> >
> >#include <reply-to-harmful.html>
> >
> >
> >------- Forwarded Message
> >
> >Date: Fri, 6 Aug 1999 08:01:21 -0700 (PDT)
> >From: Joe <josepha48@yahoo.com>
> >Reply-To: joeja@mindspring.com
> >Subject: Re: berserko mouse.
> >To: David Woodhouse <David.Woodhouse@mvhi.com>
> >
> >
> >> I haven't been following this thread, but I've recently
> >> noticed a thread on
> >> the X development list which rings a bell.
> >
> >this has ben a long thread.. to sum it up, there exists a
> >problem in X where a mouse will suddenly go bezerko. It was
> >first suspected to be SMP exclusive, but further probing into
> it
> >showed that it was not SMP specific as it occurs on UP
> machines
> >too.
> >
> >It isnot just with the PS/2 either it is also with serial
> mice
> >as I have a serial mouse, and there are others with PS/2 and
> >serial mouse that are being affected.
> >
> >This morning I got it again and did an Alt-Ctrl-F1 then
> >Alt-Ctrl-F7 and the mouse was restored, so I believe that we
> >have some kind of buffer problem
> >
> >> Basically, the ACK from the PS/2 port is no longer
> >> automatically flushed, and
> >> remains on the input queue for the port, which can cause
> the
> >> mouse driver to
> >> get out of sync with the mouse.
> >
> >not sure what teh ACK is, but yes the mouse driver is getting
> >out of sync, however it is not just the PS/2 mice, as I said
> >above it is also serial mice too. It seems that we may not be
> >flushing our buffers and thus getting bad data .. some people
> >have also reported that there keyboards stopped working also
> ..
> >
> >> This has been possible since the PS/2 mouse driver was
> moved
> >> into the keyboard
> >> driver some time around 2.1.late.
> >
> >sounds similar, but it does not explain why serial mice are
> also
> >affected, coudl this effect serial mice too?
> >
> >> Could this be your problem? If so, get back to me and I'll
> dig
> >> deeper into
> >> exactly what the fix was.
> >
> >thanks in advance...
> >
> >Joe
>
>
>
>

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