Re: how to notify blindly created 'all_partitions' to dbus, HAL, gvm

[Kay Sievers <kay.sievers@vrfy.org>]

On Sun, Apr 11, 2004 at 03:57:33PM +0200, David Zeuthen wrote:
> On Sun, 2004-04-11 at 14:11, Kay Sievers wrote:
> > We have a feature in udev to create all 15 partitions for a removable
> > media device without looking at it. It's needed cause most of the devices
> > never notify about a media change and with a fully dynamic /dev we need
> > to access one partition to force the kernel to revalidate the device.
> > This all couldn't be avoided without polling :(
> > 
> > Now as we create nodes, should we execute the /etc/dev.d/ programs for
> > the "blind" partition nodes? What are the implications for HAL, gvm?
> > 
> > And should we fake the DEVPATH for it, huhh...?
> > 
> 
> FWIW, I don't think it's necessary to execute the /etc/dev.d/ programs
> for this. Since HAL actually poll the top-level block devices, e.g.
> /dev/sda, it means that when media is inserted, the kernel invokes
> hotplug for the appropriate block device, e.g. /dev/sda1 and then
> everything is business as usual. Same story for when the media is
> removed because HAL keeps on polling even though there is media
> inserted. 

Cool, problem is gone. I like it.

> This works pretty well with my 6in1 card reader and inserting/removing a
> CF card, in fact it feels pretty sleek to see the icon appear on the
> desktop. Wrt. gnome-volume-manager, this is just a simple policy engine
> that listens for events from HAL, mounts volumes as appropriate and
> optionally stars some programs if it detects pictures on the device
> (yeah, layers upon layers :-)
> 
> On the other hand it doesn't hurt a lot to exec the programs, HAL will
> just ignore it since the DEVPATH is invalid, but note that for my 6in1
> reader (with 4 LUN's) this means 60 extra invocations! As far as I
> recall the only reason for creating all the 15 devices is compatibility
> and convenience, right? 

Yes right. After a discussion on lkml, Linus asked for it.

I just stumbled upon, cause I have a similar device and the following udev rule:

  BUS="scsi", KERNEL="sd*", SYSFS{model}="USB Storage-CFC", NAME{all_partitions}="compactflash"

The first partition is called compactflash1 and it's in /etc/fstab, but
gvm wasn't recognizing my "photos" ...
A simple explicit rule for the partition and this name in fstab fixes this,
but anyway, seems with HAL, I will never need 'all_partitions' again. :)

thanks,
Kay



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