Re: Recommendation for activating a deferred module init in thekernel

From: Johannes Stezenbach
Date: Wed Jun 18 2008 - 05:38:30 EST


On Wed, Jun 18, 2008, Stefan Richter wrote:
> Johannes Stezenbach wrote:
>> I think the USB bus enumeration can take significant time:
>> recognize a device is connected, turn on bus power, try
>> to read descriptors (bus powered devices might be slow to
>> respond after power up). And this will happen even with
>> drivers_autoprobe == 0, right?
>
> Probably... I don't know which particular steps happen in the USB core
> before upper layer drivers are bound. Not binding the [eou]hci-hcd PCI
> driver would certainly be more effective.

Well, in embedded systems you often don't have a PCI bus,
but platform devices. Maybe it's as simple as delaying
the USB platform_device_register() call, I don't know.

Johannes
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