[lkml]   [2002]   [Sep]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Subjectdelay before open() works
Hi -- I notice in 2.4 kernels that there's a delay between completion of
"modprobe scanner" and when the device file can be successfully opened. I'm
working on code to power-up devices on-demand.

I've played some with making scripts to work around this, like

heyu turn on scanner
modprobe scanner
sleep 15

This is pretty gross, since I have to determine the "15" by playing with it,
and I'm sure it will fail some of the time unless I make it reeeeeally long. I
suspected this was some hardware issue -- USB latencies on device discovery, or
boot time for the scanner -- but a friend who isn't attempting to power-up his
devices says he sees the same behavior when just scripting "modprobe". So it
appears there's some fairly long delay in the kernel itself.

Anyone know off-hand what causes this delay, or if there's some way to get
the open() to block?

(btw, I'm not subscribed to the list).
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 13:28    [W:0.088 / U:0.316 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site