Re: [PATCH] omap2+: add drm device

Tomi Valkeinen
2012-03-07T13:11:44Z

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On Wed, 2012-03-07 at 07:06 -0600, Rob Clark wrote:
> On Wed, Mar 7, 2012 at 5:59 AM, Tomi Valkeinen <tomi.valkeinen@ti.com> wrote:

> > Hmm, why does the drm core care about it?
>
> Because it is the one generating the bus-id.. see
> drivers/gpu/drm/drm_platform.c drm_platform_set_busid()
>
> Anyways, it's just a detail about how libdrm/drmOpen() can
> differentiate between multiple instances of the same driver, similar
> to how PCI bus-id is used in the desktop world. It is not difficult
> to change in drm_platform_set_busid(), although not sure if that would
> be considered an ABI change to userspace. (Maybe it is less critical,
> I'm under the impression that other platform-drm users didn't even
> realize we had a bus-id.)

Ok. Well, I'm fine with id 0 also, if it makes sense in the DRM side. It
was just something that caught my eye.

> > Okay, let me ask the other way. Is 32MB enough for everyone? Hardcoding
> > a value like that without any possibility to adjust it just sounds like
> > a rather bad thing.
>
> The main requirement is that, on omap3 or before (platforms without
> DMM) you need enough to allocate all of your scanout buffers.
>
> I'm not against having a bootarg to adjust, although I strongly prefer
> sane defaults and not requiring a million bootargs just to boot in
> some usable fashion.

Well, those are two different things. I'm fine with a default of 32MB.
My point was, what if I need more, or I don't need any.

Tomi

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