Re: Comments about commit 'PCI: docking station: remove dock uevents'?

[Holger Macht <hmacht@suse.de>]

On Mon 13. Nov - 11:54:23, Kristen Carlson Accardi wrote:
> On Mon, 13 Nov 2006 12:14:37 +0000
> Matthew Garrett <mjg59@srcf.ucam.org> wrote:
> 
> > On Sun, Nov 12, 2006 at 03:07:37PM +0100, Holger Macht wrote:
> > 
> > > I'm currently looking at docking station support for various
> > > laptops/vendors and what can be done to get them working. At the moment,
> > > userspace has to do some quirks to get support for them. For instance,
> > > when docking an X60 into a docking station where a SATA DVD drive is
> > > located, userland has to rescan the scsi host for the drive to show up.
> > 
> > Does the docking not generate a bus rescan event on the SATA bus? If it 
> > does, it's just a special case of ACPI drive hotplugging. You can't do 
> > it reliably from userspace, but I think Kirsten has been looking at 
> > doing it properly in the kernel.
> 
> When you use the "bay" driver in addition to the "dock" driver (bay is 
> in -mm right now) you would get a notification on dock/undock in the driver
> which would then cause the bay driver to notify user space about the 
> drive event.  I've not found any other devices that require user space
> notification.

Ok, thanks for the pointer, I'll have a look at it.

Regards,
	Holger

> 
> > 
> > > Additionally, currently the dock driver automatically executes the _DCK
> > > method when it detects a dock/undock event. Wouldn't it be good to have
> > > common sysfs interface for docking so that userland can trigger the
> > > dock/undock? This way userland would also be able to do 'something before'
> > > docking/undocking, such as unregistering a device, showing a poput that it
> > > is now save to physically undock, etc.
> > 
> > When the dock contains a drive, I think there's possibly an argument in 
> > favour of this. Otherwise, the hardware should be able to deal with it - 
> > every ACPI-based dock I've played with has had some indication to inform 
> > the user that the device has disconnected.
> 
> I think there is an arguement in favor of this, but there are more arguments
> in favor of not waiting for user space before executing the acpi _DCK to
> undock - mainly because not all dock stations actually lock the laptop
> in the dock, and so the user is going to just do it anyway.  by undocking
> as soon as we get the hardware notification, we can at least clean up
> after this activity.  Also, most people who have commented on my bay driver
> (which does assume user space handles the actual eject) have complained
> about the fact that I wait for user space.  they general feedback I've gotten
> is that these activities should "just happen" and not require user intervention.
> 
> 
> > 
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