Messages in this thread |  | | Date | Sat, 14 Sep 2002 09:42:25 -0700 | From | Brian Craft <> | Subject | delay 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 xsane
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). b.c. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |