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How usb hotplug works [really: input hotplugging]

DISCUSSION David Brownell 1 participant 1 message Jan 17, 2001

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Quoted 1 line

I cannot get works actually hotplug with a simple usb keyboard :

Well, it should ... I'll have to verify the latest RPM, to be sure it still behaves with mine!

On the other hand, that isn't a "simple" keyboard: it has a mouse.

Quoted 7 lines

--=-=-> T: Bus Lev Prnt Port Cnt Dev#= 3 Spd=1.5 MxCh= 0

D:  Ver= 1.00 Cls(>ifc ) Sub Prot MxPS= 8 #Cfgs=  1
P:  Vendora4 ProdID™98 Rev= 1.00
S:  Manufacturer=NOVATEK
S:  Product=USB Keyboard

C:* #Ifs= 2 Cfg#= 1 Atr  MxPwr0mA
I: If#= 0 Alt= 0 #EPs= 1 Cls(HID ) Sub Prot Driver=(none)

                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

That should cause "hid" to be loaded, at least.
Then /etc/hotplug/usb.handmap should add "keybdev" (and input).

Since it seems neither of those happened, I suspect that you were trying to use a "usbmodules" that doesn't know about the modutils 2.4.1 output. Or something else broke, and we'd like to know what.

Quoted 2 lines
E:  Ad�(I) Atr(Int.) MxPS=   8 Ivl= 10ms
I:  If#= 1 Alt= 0 #EPs= 1 Cls(HID  ) Sub Prot Driver=(none)
                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

There are two ways to get that second interface to trigger module
loading: (a) "usbmodules" would figure it out from usbdevfs;
(b) "usb.handmap" can list that specific device. I just updated "usb.handmap" to know about this funky device.

Assuming Linus merges the usb-storage patch, then the main use for the "handmap" file is going to be coping with various kinds of funky HID devices (like this keyboard/mouse combo).

Eventually the input system needs to learn to hotplug. ADB users need that kind of solution, and device-specific mappings aren't particularly desirable given how many different HID devices exist.

Quoted 5 lines

i have also to setup a :

post-install usbkbd modprobe keybdev

in my /etc/modules.conf

That seems strange. I thought it was only the HID based driver which needed the input subsystem and "keybdev". The boot protocol driver is discouraged for everything except systems with really constrained resources, it's not as functional.

- Dave

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