what I did to hotplug Phillips/Logitech webcams
Hello,
I'd like to describe what I had to do to hotplug-2001_01_16-2.noarch.rpm in order to be able to hotplug a Phillips/Logitech 730K USB camera.
Some of my mods may be a result of not groking hotplug. Some could be because hotplug is a work in progress. In other words, it is a bug or a feature? :-)
=-
Here is what we wanted to do:
Plug on a Logitech QuickCam 3000 Pro (USB webcam that is a Phillips 730K) and have the right magic occur with the pwc and pwcx-i386 modules.
There are two other items that are needed:
1) We need the modprobe to be:
modprobe pwc size=vga power_save=1 fps \
compression=0 mbufs=2 leds%0,750
not just 'modprobe pwc'.2) After pwc is loaded, we need to load the pwcx-i386 module which is a binary-only module :-( that requires something like:
/sbin/insmod --force /etc/hotplug/usb/pwcx-i386.o >/dev/null 2>&1
We wanted the webcam modules loaded at boot time if the camera was plugged in. We also wanted them to be loaded if hotplug was restarted.
=-
Our hack/solution:
We started with the 2002_01_14-1 hotplug code, installed from
the hotplug-2002_01_14-1.noarch.rpm file.
We added the following line to /etc/hotplug/usb.usermap:
pwc 0x0003 0x046d 0x08b0 0x0000 0x0000 0x00 0x00 0x00 0x00 0x00 \
0x00 0x00000000
We created the following executable file:
/etc/hotplug/usb/pwc
containing the following lines:
#!/bin/bash
modprobe pwc size=vga power_save=1 fps compression=0 mbufs=2 \
leds%0,750
/sbin/insmod --force /etc/hotplug/usb/pwcx-i386.o >/dev/null 2>&1In order to get that to work, we had to make the following patch to hotplug.functions:
*** hotplug.functions.init Fri Feb 22 11:09:10 2002
--- hotplug.functions Fri Feb 22 11:07:53 2002
***************
*** 10,16 ****
# $Id: hotplug.functions,v 1.8 2002/01/07 18:16:46 dbrownell Exp $ #
! # DEBUG=yes export DEBUG
PATH=/bin:/sbin:/usr/sbin:/usr/bin
KERNEL=uname -r
--- 10,16 ----
# $Id: hotplug.functions,v 1.8 2002/01/07 18:16:46 dbrownell Exp $ #
! # DEBUG=yes; export DEBUG
PATH=/bin:/sbin:/usr/sbin:/usr/bin
KERNEL=uname -r
***************
*** 132,151 ****
# maybe driver modules need loading
# either kernel or user mode drivers may need to be set up
for MODULE in $DRIVERS
do
if ! lsmod | grep -q "^$MODULE "; then
! if grep -q "^$MODULE\$" /etc/hotplug/blacklist \
>/dev/null 2>&1; then
debug_mesg "... blacklisted module: $MODULE"
# user mode drivers will ONLY have a setup script,
# so it's not an error if a module doesn't exist
elif $MODPROBE -n $MODULE >/dev/null 2>&1 &&
! $MODPROBE $MODULE >/dev/null 2>&1 ; then
mesg "... can't load module $MODULE"
- elif [ -x /etc/hotplug/$TYPE/$MODULE ]; then
- debug_mesg Module setup $MODULE for $DESCRIPTION
- /etc/hotplug/$TYPE/$MODULE
else
mesg "missing kernel or user mode driver $MODULE "
fi
--- 132,155 ---- # maybe driver modules need loading
# either kernel or user mode drivers may need to be set up
+ if [ -n "$HOTPLUG_DIR" ]; then
+ HOTPLUG_DIR=/etc/hotplug
+ export HOTPLUG_DIR
+ fi
for MODULE in $DRIVERS
do
if ! lsmod | grep -q "^$MODULE "; then
! if grep -q "^$MODULE\$" $HOTPLUG_DIR/blacklist \
>/dev/null 2>&1; then
debug_mesg "... blacklisted module: $MODULE"
+ elif [ -x $HOTPLUG_DIR/$TYPE/$MODULE ]; then
+ debug_mesg Module setup $MODULE for $DESCRIPTION
+ $HOTPLUG_DIR/$TYPE/$MODULE
# user mode drivers will ONLY have a setup script,
# so it's not an error if a module doesn't exist
elif $MODPROBE -n $MODULE >/dev/null 2>&1 &&
! $MODPROBE $MODULE >/dev/null 2>&1 ; then
mesg "... can't load module $MODULE"
else
mesg "missing kernel or user mode driver $MODULE "
fiA few notes on the above patch to hotplug.functions:
1) The ; is missing from the commented out DEBUG line. We made use of debugging while trying to figure things out.
2) We found cases where $HOTPLUG_DIR was not defined during execution of the load_drivers() shell function. While hotplug.functions may define HOTPLUG_DIR, it does not export it. During testing we found it easier just to check for a missing/empty HOTPLUG_DIR and set it inside the load_drivers() shell function.
3) We fixed a case where /etc/hotplug was still hard coded.
4) The most critical patch:
We needed $HOTPLUG_DIR/$TYPE/$MODULE checked before a modprobe was done. The way it was written, a modprobe of pwc would always succeed and our script would never be executed. The pwc module would not be loaded with the desired flags and would be ignored altogether.
We also had to patch the usb.rc file:
*** usb.rc.init Thu Feb 21 05:13:37 2002
--- usb.rc Thu Feb 21 05:30:03 2002
***************
*** 53,59 ****
# synthesize hotplug events if we can
# we need (non-bash) programs to parse descriptors.
LISTER=`type -p usbmodules`
! if [ "$LISTER" = "" -o ! -f /proc/bus/usb/devices ]; then
echo $"** can't synthesize root hub events"
return
fi
--- 53,59 ----
# synthesize hotplug events if we can
# we need (non-bash) programs to parse descriptors.
LISTER=`type -p usbmodules`
! if [ ! -f /proc/bus/usb/devices ]; then
echo $"** can't synthesize root hub events"
return
fi
***************
*** 68,74 ****
export DEVFS DEVICE # these notifications will be handled by pcimodules
! for DEVICE in /proc/bus/usb/*/*
do
/etc/hotplug/usb.agent
done
--- 68,74 ----
export DEVFS DEVICE # these notifications will be handled by pcimodules
! for DEVICE in /proc/bus/usb/[0-9][0-9][0-9]/[0-9][0-9][0-9]
do
/etc/hotplug/usb.agent
done
***************
*** 81,92 ****
COUNT=0
SYNTHESIZEúlse- # if USB is partially initted, synthesize hotplug events since
- # the kernel probably dropped them (missing root, unwritable /tmp)
- if [ -d /proc/bus/usb -a `ls /proc/bus/usb 2>&1 | wc -l` -gt 2 ]; then
- SYNTHESIZE=true
- fi
-
# if distro hasn't already done part of this ... load core,
# and mount usbdevfs before the first hotplug agent fires
# (so it'll be available to the agents).
--- 81,86 ----
***************
*** 134,139 ****
--- 128,139 ----
return 1
fi+ # if USB is partially initted, synthesize hotplug events since
+ # the kernel probably dropped them (missing root, unwritable /tmp)
+ if [ -d /proc/bus/usb -a `ls /proc/bus/usb 2>&1 | wc -l` -gt 2 ]; then
+ SYNTHESIZE=true
+ fi
+
# hotplug events didn't fire during booting;
# cope with devices that enumerated earlier
# and may not have been fully configured.A few notes on the above patch to usb.rc:
1) We did not have the usbmodules file. LISTER was always empty and we always got a 'can't synthesize root hub events'.
2) Running /etc/hotplug/usb.agent over [0-9][0-9][0-9]/[0-9][0-9][0-9] is a bit more exact than just */*
3) The test for /proc/bus/usb, when performed BEFORE the mounting of /proc/bus/usb would fail. By moving this test later on, SYNTHESIZE=true would be set and usb_boot_events would be executed. This allowed for an already plugged in webcam to be discovered.
Although I realize that the intention was boottime, restarting hotplug (via /etc/init.d/hotplug) could happen AFTER /proc/bus/usb was mounted. Additionally for those who put:
none /proc/bus/usb usbdevfs defaults
in their /etc/fstab, /proc/bus/usb is mounted well before hotplug starts.
Last, somebody who changes a parameter in something like /etc/hotplug/usb/foo would like to be able to restart hotplug and have devices detected.
Comments welcome.
chongo (Landon Curt Noll) /\oo/\
p.s.: Here is some background info on Phillips/Logitech USB drivers:
http://www.smcc.demon.nl/webcam/
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