Re: loading firmware while usermodehelper disabled.

Am Dienstag, 3. Januar 2012, 06:53:46 schrieb Linus Torvalds:

On Mon, Jan 2, 2012 at 7:25 PM, Matthew Garrett [off-list ref] wrote:

quoted

On Mon, Jan 02, 2012 at 09:45:58PM -0500, Alan Stern wrote:

quoted

Wait a second.  Why does isight_firmware bind at this time?  Binding to
new devices is handled by khubd, which doesn't start running again
until after the resume is finished (the device appears to be new
because its descriptors have changed).  At that point there should be
no trouble reloading the firmware.

Then why are we getting this warning? The firmware is only loaded in the
probe function.

The USB suspend/resume function does that "unbind/rebind" dance, and
that causes a "device_attach()". Which causes a probe() to be called.

Should it do that? I think not, not if the ID's haven't changed. But I
don't know the USB layer all that well.

The ID has changed. That is why we run into this problem.
And indeed the USB layer does the rebind only if either

a) ID has changed
b) the driver tells us that it cannot deal with a device that has lost its state

The whole USB suspend/resume code is also very confused in general.
See for example commit c043f1245654 ("USB: unbind all interfaces
before rebinding them") which talks about how the USB layer needs to
unbind all interfaces in order to rebind them later.  But then you
look at the *code*, and it actually does a DO_REBIND, not an unbind!

Understood. Working on that.

	Regards
		Oliver