#263 lsof reveals wacom input driver opening hundreds of redundant descriptors, exhausting X resources
lsof -n -p pidof Xorg.bin reveals hundreds of open descriptors to /dev/input/event5 and /dev/input/event6. Consulting Xorg.0.log shows those are "Wacom Intuos3 4x6" and "Wacom Intuos3 4x6 Pad" I am pretty sure this is what's causing Xorg to run out of resources and say "maximum number of clients reached" instead of opening a window, or other X client connection. There are no further log entries referring to the Wacom devices.
Just one tablet. I do not have 258 distinct Wacom devices plugged into my computer.
This happens regardless of whether I am using the tablet, and in fact I should draw more often because I forgot I had left it plugged in. This happens after about a week online maybe, so the leaked descriptors accumulate slowly over a large period of time.
Unplugging the tablet causes several "Error reading wacom device" messages, then "config/udev: removing device Wacom" as is expected. Another 'lsof -n -p pidof Xorg.bin' though reveals that all the two hundred descriptors are still open, pointing now at deleted files. They never seem to get cleaned up without restarting X.
I'm on an Arch Linux system updated (pretty) recently with "X.Org X Server 1.16.2" and wacom input driver's module version = 0.27.0. XInput ABI version 21. It's an old Wacom Intuos 3, if that's not obvious. Kernel version 3.17.2-1-ARCH using the wacom drivers that come with it.
Discussion
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While I try to reproduce this, can you tell me if your system is set to suspend and resume? Leaking once per cycle would imply 129 suspend & resume cycles over the course of a week (which seems a little extreme), but it still seems like as good a place as any to start investigating.
If you're comfortable building and installing the driver from source[1], please try applying the attached patch and letting me know if it resolves your issue.
Fixed in xf86-input-wacom 0.28.0