[RFC] drm platform multi-device support

Dave Airlie airlied at gmail.com
Tue Apr 5 18:21:48 PDT 2011

On Tue, Apr 5, 2011 at 1:08 PM, Rob Clark <robdclark at gmail.com> wrote:
> On Mon, Apr 4, 2011 at 7:30 PM, Dave Airlie <airlied at gmail.com> wrote:
>> On Wed, Mar 30, 2011 at 2:44 AM, Rob Clark <rob at ti.com> wrote:
>>> From: Rob Clark <robdclark at 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?

Yup that seems a lot saner and more acceptable.


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