Re: [PATCH 003/117] Staging: hv: Add struct hv_vmbus_device_id to mod_devicetable.h

On Wed, Aug 24, 2011 at 09:51:00PM +0000, KY Srinivasan wrote:

quoted

It would allow you, in your probe function, to do something different
depending on the guid that the probe function was matching on.  So you
would not have to check the guid again to do that, just use the data
pointed in that void pointer and away you go.

As an example, look at drivers/usb/class/cdc-acm.c, the acm_ids[]
variable which uses the driver_info field to contain a quirk for the
device.

Ok; this makes sense. But I currently don't have any quirks to support!

That was just an example.

The util driver is not even a driver in the true sense. I made it a driver and
added the probe function just to support auto-loading with the vmbus ID space
that I am trying to implement here - the probe function does nothing.

As you can tell, I'm trying to say that is wrong :)

the hv_util.c driver should have a pointer in each of the driver_info
that describes what it is, and then in the probe function, you use that
to hook up the correct things needed.

None of this hard-coded mess like you currently have.

Trust me, you want that pointer, put it in, and if you never use it,
I'll buy you a beer.  But if I send you a patch using it, well...

quoted

quoted

I looked at the usage of this in PCI and it appears to be for supporting
dynamic  IDs for existing drivers.

No, that's exactly wrong.  dynamic ids play havoc with this pointer,
making some drivers not be able to handle dynamic ids because they rely
on it for some driver-specific information to be passed in it, which
dynamic ids can not handle.

Oh, have you remembered to turn off dynamic ids for these devices?  Or
do you support them properly?

I don't support dynamic IDs. What would I need to do to turn it off.

Ah, nevermind, that is something that busses add in their core if they
want it.  I added it for PCI and USB, maybe I should move that to the
driver core so that others can get it automatically one of these days...

thanks,

greg k-h