Date: Sat, 20 Jan 2018 18:16:43 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 225341] System locks up due to atkbd_timeout kludge when using /dev/atkbd0 directly Message-ID: <bug-225341-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D225341 Bug ID: 225341 Summary: System locks up due to atkbd_timeout kludge when using /dev/atkbd0 directly Product: Base System Version: CURRENT Hardware: amd64 OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: freebsd-bugs@FreeBSD.org Reporter: jan.kokemueller@gmail.com There is a timer in atkbd that is called 10 times per second. It seems to b= e a kludge that is used to unwedge keyboard interrupts [1]. Unfortunately, if I keep this in, my system locks up after a brief period of usage. I don't really know how to debug this -- the system just hangs. One important bit of information: I don't use the atkbd device in its defau= lt configuration behind the kbdmux0 device. Instead, I detach it from kbdmux0, open it directly and parse the keyboard data in userspace [2]. I feed the d= ata into an Evdev device and a vkbd(4) device for use in vt(4). In the default configuration (atkbd0 attached to kbdmux0) the issue is mask= ed. I haven't noticed any negative effects by disabling the atkbd_timeout timer. I'm using a Lenovo Thinkpad T420. I suspect it has to do with locking issues. There have been some attempts to improve locking in atkbd and psm [3] but it turned out that this locking approach could not be used [4]. [1]: https://svnweb.freebsd.org/base/head/sys/dev/atkbdc/atkbd.c?revision=3D3262= 55&view=3Dmarkup#l161 [2]: https://github.com/jiixyj/evdevfbsd/blob/e64ae7da580c9ccede482b380440d7b463= 6b4943/backend-atkbd.c#L108 [3]: https://lists.freebsd.org/pipermail/freebsd-arch/2017-May/018193.html [4]: https://reviews.freebsd.org/D10263#221930 --=20 You are receiving this mail because: You are the assignee for the bug.=
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