Question about enable polling.

[David Zeuthen]

Hi,

For the record, the docs are located here

 http://hal.freedesktop.org/docs/udisks/

Also note that the ABI of the udisks(1) binary isn't considered
stable. The D-Bus ABI has some stability gurantees, see the README
file.

On Sat, Oct 2, 2010 at 10:43 AM, Stef Bon <stef at bononline.nl> wrote:
> I'm using the udisks to activate the polling like:
>
> udisks --poll-for-media /dev/sr0

You got it wrong - polling is not something that is "activated" - it's
something the daemon does by default for all devices with removable
media. The only reason --poll-for-media is there is to make it
possible poll devices that are not polled by default - e.g. PC floppy
devices.

> b. Why does it poll the usb devices anyway? The kernel and udev handles
> everything correct right, so why does udisks bother?

No. The kernel only handles the USB device being yanked, not media
removed from the device itself. While the former is good enough for
e.g. USB attached hard disks (that are not removable) it is not good
enough for e.g. card readers (that are removable).

Unfortunately many devices incorrectly report whether they support
removable media or not - for example USB sticks do that a lot (a USB
stick is hotpluggable, not removable). One downside of that is that we
poll them even when we don't need to. It's not a big problem.

     David