Re: [RFC] drm platform multi-device support

[Rob Clark <robdclark@gmail.com>]

On Mon, Apr 4, 2011 at 7:30 PM, Dave Airlie <airlied@gmail.com> wrote:
> On Wed, Mar 30, 2011 at 2:44 AM, Rob Clark <rob@ti.com> wrote:
>> From: Rob Clark <robdclark@gmail.com>
>>
>> Include the minor device id in the bus-id to give userspace a way to open
>> the correct "cardN" when there are multiple device instances.
>> ---
>> It may seem a bit strange to have multiple platform device instances, but
>> we have a use-case for this.  And this relatively simple patch does the
>> trick.
>
> I'm finding it hard to like this since I feel it might limit certain
> thing in the future, by baking
> this into the ABI.
>
> We have plans for multiple device nodes per device, but they don't
> involve abusing the bus id like this.
>
> Surely you'd just have another platform device with another unique
> name for this, I'd be more willing
> to accept some sort of unique id stored in the platformdev or drm that
> isn't the device node.

What about:

		len = snprintf(master->unique, master->unique_len,
			"platform:%s:%02d", dev->platformdev->name, dev->platformdev->id);

(ie. using the id field from struct platform_device)..

Perhaps this is more analogous to using pci bus # / slot / func?

BR,
-R