RE: [PATCH 00/20] prime/flink fixes and related stuff

[Inki Dae <inki.dae@samsung.com>]

> -----Original Message-----
> From: Daniel Vetter [mailto:daniel.vetter@ffwll.ch]
> Sent: Monday, August 05, 2013 2:42 AM
> To: Inki Dae
> Cc: DRI Development
> Subject: Re: [PATCH 00/20] prime/flink fixes and related stuff
> 
> On Sat, Jul 27, 2013 at 11:22 AM, Inki Dae <inki.dae@samsung.com> wrote:
> >
> > 2013/7/16 Daniel Vetter <daniel.vetter@ffwll.ch>
> >>
> >> Hi all,
> >>
> >> This patch series is my 2nd real stab at fixing up the locking issues
> >> around our
> >> two buffer sharing mechanisms in gem: flink and prime.
> >>
> >> I think the approach taken here is much better than my first stab, and
> it
> >> also
> >> seems to no longer leak buffers ;-) There some assorted cleanup and
> prep
> >> work
> >> (and one i915 fix) thrown into the mix, it's all stuff I've stumbled
> over
> >> while
> >> digging through the code.
> >>
> >> Open issues left in prime-land after these patches:
> >> - exynos probably wants a similar patch to "drm/i915: explicit store
> base
> >> gem
> >>   object in dma_buf->priv". The current code should be correct, but
> it's a
> >> bit
> >
> >
> > How about using stuffs of drm_prime instead of specific ones? Seem like
> that
> > we could replace specific dmabuf stuffs with common ones of drm_prime,
> at
> > least in case of Exynos: i.e. each driver can export a gem to a dmabuf
> > through drm_gem_prime_export function of drm_prime instead of specific
> one.
> > By doing so, I think we could remove duplicated codes of drivers,
> specific
> > dmabuf stuffs. I'm not sure but it seems like that there is any reason
> you
> > try to use existing stuffs with a little change: maybe the stuffs of
> > drm_prime couldn't be used for all drm drivers commonly.
> 
> I have to admit that I didn't really understand your email, mostly
> since you talk about "stuff" and "stuffs" and I didn't really grok
> which piece of code you actually mean. Can you pls elaborate, maybe
> taking the functions for exynos as an example?

You have posted one patch that makes i915/exynos drivers use
drm_gem_dmabuf_release function commonly. But my opinion is that we could
use not only drm_gem_dmabuf_release function but also other functions of
drm_prime commonly. I think that could be done simply like below,

In drivers/gpu/drm/i915/i915_dev.c,
	Static struct drm_driver driver = {
		...
		.gem_prime_export = drm_gem_prime_export,
		.gem_prime_import = drm_gem_prime_import,
		...

We are using driver specific dma_buf_ops, i915_dmabuf_ops for i915 and
exynos_dmabuf_ops for exynos. So my opinion is to use
drm_gem_prime_dmabuf_ops of drm_prime instead. However, for this, we have to
change specific export and import functions to exported drm_prim's ones,
drm_gem_prime_export and drm_gem_prime_import. And I thought maybe you
caught that but you used only drm_gem_dmabuf_release function among them of
drm_prime if there is no my missing point. So I guess maybe there is any
reason in doing so.

Thanks,
Inki Dae

drm: use common drm_gem_dmabuf_release in i915/exynos drivers


> -Daniel
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch