From: Kay Sievers <kay.sievers@vrfy.org>
To: linux-hotplug@vger.kernel.org
Subject: Re: Accessing usb devices with USBDEVFS
Date: Sat, 29 Apr 2006 13:06:08 +0000 [thread overview]
Message-ID: <20060429130608.GB13319@vrfy.org> (raw)
In-Reply-To: <44525468.5030106@ist-traffic.com>
On Fri, Apr 28, 2006 at 01:44:08PM -0400, Danny Budik wrote:
> I have a question that may or may not be related to hotplugging. I have
> noticed that when I plug in a USB device, it takes about 5 seconds for
> it to show up in /proc/bus/usb/001/xxx. I am using HAL to recognize when
> a USB device is plugged in and USBDEVFS to communicate with my device.
>
> When I plug it in, dbus/HAL instantly recognizes it and sends me a
> message. But when I make the function call to open it (using fopen on
> the file above) I get an error that the device is not found. In fact, it
> takes about 5 seconds for the device to show up in the /proc/bus/usb/
> directory so I have to place a sleep(5) line in my C code before I am
> able to open the device.
>
> My test machine is a PIII 733 with FC4, latest kernel, so it is a
> relatively slow machine. Is there a way to predict the time that it
> takes for the device to be accessible with USBDEVFS so that I don't have
> to hardcode the sleep statement?
Recent systems don't use /proc for usb access anymore and real device
nodes in /dev/bus/usb instead. HAL sends "usbraw" device anouncements with
"linux.device_file" as a property when the device is created.
Kay
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next prev parent reply other threads:[~2006-04-29 13:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-28 17:44 Accessing usb devices with USBDEVFS Danny Budik
2006-04-28 21:14 ` Greg KH
2006-04-29 13:06 ` Kay Sievers [this message]
2006-05-01 15:39 ` Danny Budik
2006-05-01 16:57 ` Greg KH
2006-05-01 19:00 ` Danny Budik
2006-05-01 19:06 ` Greg KH
2006-05-01 19:09 ` Kay Sievers
2006-05-05 20:45 ` Danny Budik
2006-05-05 21:02 ` Greg KH
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