Dear All,
I am seeing a 2-second pause while booting which I hypothesize is due
to a locking interaction between the mouse system and the platform bus
system. Here's a fragment from dmesg:
[ 2.202156] serio: i8042 KBD port at 0x60,0x64 irq 1
[ 2.202170] serio: i8042 AUX port at 0x60,0x64 irq 12
[ 2.202183] initcall i8042_init+0x0/0x32a returned 0 after 29 msecs
[ 2.202191] calling serio_raw_init+0x0/0x11 @ 1
[ 2.202345] initcall serio_raw_init+0x0/0x11 returned 0 after 0 msecs
[ 2.202356] calling mousedev_init+0x0/0x72 @ 1
[ 2.202638] mice: PS/2 mouse device common for all mice
[ 2.202648] initcall mousedev_init+0x0/0x72 returned 0 after 0 msecs
[ 2.202657] calling evdev_init+0x0/0xa @ 1
[ 2.208739] initcall evdev_init+0x0/0xa returned 0 after 5 msecs
[ 2.208746] calling atkbd_init+0x0/0x1b @ 1
[ 2.208855] initcall atkbd_init+0x0/0x1b returned 0 after 0 msecs
[ 2.208864] calling psmouse_init+0x0/0x58 @ 1
[ 2.232546] input: AT Translated Set 2 keyboard as /class/input/input5
[ 2.247037] initcall psmouse_init+0x0/0x58 returned 0 after 36 msecs
[ 2.247047] calling pcspkr_init+0x0/0xa @ 1
[ 2.247067] pcspkr_probe starting
[ 2.249202] input: PC Speaker as /class/input/input6
[ 2.259239] pcspkr_probe done
[ 4.379527] input: ImPS/2 Logitech Wheel Mouse as /class/input/input7
[ 4.387077] initcall pcspkr_init+0x0/0xa returned 0 after 2040 msecs
Note that the pause is between pcspkr_probe returning and pcspkr_init
returning. My guess is that during this time the platform bus is
matching the pcspkr driver against all the other platform devices, and
in order to do so it is taking various device locks; at the same time
the kpsmoused workqueue is locking one of the same devices and spending
a couple of seconds probing it. But that's only a guess based on a
couple of hours work; no doubt you experts will have a better idea of
what's going on.
What can be done about this? Is it unreasonable for the mouse probing
to take 2 seconds? Should it not be holding the conflicting lock while
it is probing? Does the platform matching code really need to hold the
lock when it's just comparing the string names of the device and driver?
This is on an ASUS Eee 901, which is the same machine that Arjan van de
Ven and Auke Kok have got to boot in 5 seconds (with only 1 second of
that in the kernel). As you can see I have some way to go still. I
would also be interested to hear if anyone knows what the touchpad in
this machine really is - is "ImPS/2 Logitech Wheel Mouse" right? I'd
like to be able to tweak things like tap-to-click and two-finger scrolling.
Cheers, Phil.
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