what I did to hotplug Phillips/Logitech webcams
This is more of a reply to "RFE" #535191 ...
Quoted 11 lines
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'.
Normally I'd expect applications to set driver modes as necessary. But if you don't want apps to know such stuff, what's wrong with having them set in /etc/modules.conf in your particular configuration?
Quoted 4 lines
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
Easily done in an /etc/hotplug/usb/... script. Or even in /etc/modules.conf ("above" or "post-install").
Quoted 2 lines
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.
Yes, that's basically what the "hotplug" in /etc/rc.d is for. Though it seems like you weren't having that do your USB initialization, and that was likely part of the problem.
Quoted 4 lines
We added the following line to /etc/hotplug/usb.usermap:
pwc 0x0003 0x046d 0x08b0 0x0000 0x0000 0x00 0x00 0x00 0x00 0x00 \
0x00 0x00000000Not needed with current PWC drivers.
As for the patches ... I second Greg's request to use "diff -u" format when posting/submitting patches, "context" diffs are harder to understand than "unified"! Going by the comments explaining them (and omitting what Greg dealt with):
Quoted 8 lines
hotplug.functions:
...
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.
Actually the bug would be that the setup script wouldn't run if the modprobe was done ... which is clearly bogus. I've noticed that happening in some cases, a fix should be in the next version. (The logic was bit too heavy on else-if ... :)
Quoted 2 lines
The pwc module would not be loaded with
the desired flags and would be ignored altogether.
See above. The normal ways to do this are with "modules.conf", or (better yet) for applications to set the driver modes they need.
Quoted 11 lines
We also had to patch the usb.rc file:
...
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.agentover [0-9][0-9][0-9]/[0-9][0-9][0-9] is a bit more exact than just */*
Actually no ... you weren't synthesizing the events correctly, since at this time only "usbmodules" is able to provide all the essential device descriptor information (from usbfs). So those two patches add up to nothing, since "*/*" is fully correct (a more constrained pattern doesn't matter).
If you were trying to debug the processing for a single event, it's better to just export the relevant environment variables from a shell script using the syslogged data, and use "sh -x" to watch the whole sequence. I can't see how you'd see some of the failures you described unless you were running scripts without correctly invoking them.
Quoted 5 lines
3) The test for
/proc/bus/usb, when performed BEFORE the mounting of/proc/bus/usbwould fail. By moving this test later on, SYNTHESIZE=true would be set andusb_boot_eventswould be executed. This allowed for an already plugged in webcam to be discovered.
If you had problems with hotplugging at boot time, they weren't caused by this. If the USB startup script was loading "usbcore" and mounting usbfs, then there's no need to synthesize hotplug events ... because real ones would be reported.
Quoted 9 lines
Although I realize that the intention was boottime, restarting hotplug (via
/etc/init.d/hotplug) could happen AFTER/proc/bus/usbwas mounted. Additionally for those who put:none
/proc/bus/usbusbdevfs defaultsin their
/etc/fstab,/proc/bus/usbis mounted well before hotplug starts.
Not quite. Hotplug for USB starts pretty much when the first host controller driver is loaded, and the connected devices start enumerating. After they're set up, "/sbin/hotplug is invoked. And if usbfs is mounted already, everything works without any need to synthesize events.
If your system boot strap procedures are initializing USB before hotplug, it's either doing it correctly (usbfs mounted before the host controller drivers are loaded), or not ... and if it's not, better to fix that than try to patch broken OS init through hotplug.
Quoted 3 lines
Last, somebody who changes a parameter in something like
/etc/hotplug/usb/foowould like to be able to restart hotplug and have devices detected.
Right, but that's happening automatically by virtue of fully stopping USB, then correctly starting it up.
- Dave
_______________________________________________
Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net
[email protected]
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel