modprobe problem with video module

[Denys Vlasenko]

On Tuesday 17 November 2009 21:04, Gordon Smith wrote:
> Hello -
> 
> I have a problem loading a particular video device module using
> busybox modprobe, both busybox 1.14.3 and today's daily snapshot.
> 
> Problem: When saa7134.ko is loaded via modprobe, internally there is a
> call to request_module("saa6752hs") in v4l2-common.c,
> once for each of two compression channels. The second call hangs for a
> few minutes. I've not seen or heard of this problem in a standard
> distro..
> My understanding is request_module() will result in a call to
> modprobe. Is that true? If so, what is the mechanism to do so?

In kernel's kmod.c, __request_module() runs

/sbin/modprobe -q -- MODULE_NAME

Replace /sbin/modprobe with this script:

#!/bin/sh
start=`date`
/PATH/TO/busybox modprobe -v "$@" >/tmp/modprobe.log.$$ 2>&1
r=$?
exec >>/tmp/modprobe.log
echo
echo "$start ... `date`"
echo "$$: $*"
cat /tmp/modprobe.log.$$
exit $r

then do that problematic modprobe, then tar up and post
all /tmp/modprobe.log* files. One of them will show which exactly
modprobe takes that long.
--
vda