On Wed, 14 Sep 2011, Daniel Stone wrote:
Hi.
On 14/09/2011, at 3:38 AM, Tim Connors <tconnors@rather.puzzling.org> wrote:
Whenever the met software is reading and/or writing to the serial port (I haven't yet debugged whether it only happens during read or write), the keyboard badly lags when in X, but not at the console. I don't *think* the mouse is affected, most of the time, unless X is waiting for the keyboard to catch up.
Very weird indeed. X doesn't do anything fancy with its keyboard handling there and in fact we don't even know that it's USB: we just process the events as we get them.
Does running evtest on the keyboard device (which you can find through /var/log/Xorg.0.log or /proc/bus/input/devices) show the same lag? If so - definitely a kernel issue.
Yep - pauses with evtest too. But again, only in X, not at the console. It also drops entire keystrokes instead of just lagging, at times.
I'm apparently using the evdev driver. In xorg.conf, synaptics is configured for the mouse, talking on /dev/psaux, and not as core pointer. corekeyboard and coremouse are left as default.
Just to be safe, I upgraded to kernel 3.0, and everything X related to debian unstable (so that's Version: 2:1.11.0-1 for xserver-xorg-core). And I moved over to Nouveau (damn frenchies. I can never spull that word correctly without consulting google-spull-correct) from nvidia. And I even deleted xorg.conf just to make sure everything is pulled in as default.
Can anyone else reproduce this? You probably don't need a USB-serial converter. It's probably just some conflict reading things from /dev/input/* or in the kernel TTY layer or something, and so any old serial connection busily talking will do it.
Nope, not on any kernel from ~2.6.32 through to 3.1rc. I use a USB-serial converter all the time and it works just fine.
It could have been back in April: [UPGRADE] xserver-xorg 1:7.6~2 -> 1:7.6+6 [UPGRADE] xserver-xorg-core 2:1.7.7-11 -> 2:1.9.5-1 [UPGRADE] xserver-xorg-input-evdev 1:2.6.0-1 -> 1:2.6.0-2 [UPGRADE] xserver-xorg-input-kbd 1:1.4.0-2 -> 1:1.6.0-1
As I said, we just process the events as the kernel sends them to us and don't even know the keyboard's a USB device. So if the delivery changes based on USB activity, I'd be looking very, very firmly at the kernel ...
Maybe my usbserial pl2303 device has daemons in it. My computers have... unique problems. The keyboard I had been using sometimes forgot to send the occasional keyup event. And indeed got confused as to whether a key was up or down. Replacing the keyboard at least fixed that problem. -- Tim Connors