unnecessary polls of cdrom block device from udisks daemon

[Aaron Lu]

Hi,

I'm doing some development on Linux scsi cdrom driver(sr module)
recently and found that the udisks daemon will periodically open the
ODD block device /dev/sr0. I guess the reason is to check events, since
on block open, the check_events function will be called.

But since the udev will also enable in kernel polling by change the
kernel parameter /sys/module/block/parameters/events_dfl_poll_msecs to 2
seconds, so the polls done by udisks daemon by a open system call for
the scsi cdrom block device should be unnecessary.

Udev did this with a rule file:
/lib/udev/rules.d/60-persistent-storage.rules

And I've tested by doing udisks --inhibit-polling /dev/sr0 and
everything still works fine.

The problems I can think of are:
1 some in kernel drivers didn't set the event value for the disk properly;
2 the udev rule file didn't change the events_dfl_poll_msecs parameter
when needed(for scsi block device, it is OK, but I'm not sure other cases).

So, do you think the poll for such devices could be set to false by
default?

Thanks,
Aaron