RE: [PATCH v2 12/26] drm/exynos: Split manager/display/subdrv

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

> -----Original Message-----
> From: Sean Paul [mailto:seanpaul@chromium.org]
> Sent: Thursday, October 17, 2013 11:37 PM
> To: Inki Dae
> Cc: dri-devel; Dave Airlie; Tomasz Figa; Stéphane Marchesin
> Subject: Re: [PATCH v2 12/26] drm/exynos: Split manager/display/subdrv
> 
> On Thu, Oct 17, 2013 at 4:21 AM, Inki Dae <inki.dae@samsung.com> wrote:
> >
> >
> >> -----Original Message-----
> >> From: Sean Paul [mailto:seanpaul@chromium.org]
> >> Sent: Thursday, October 17, 2013 4:27 AM
> >> To: dri-devel@lists.freedesktop.org; inki.dae@samsung.com
> >> Cc: airlied@linux.ie; tomasz.figa@gmail.com; marcheu@chromium.org; Sean
> >> Paul
> >> Subject: [PATCH v2 12/26] drm/exynos: Split manager/display/subdrv
> >>
> >> This patch splits display and manager from subdrv. The result is that
> >> crtc functions can directly call into manager callbacks and encoder
> >> functions can directly call into display callbacks. This will allow
> >> us to remove the exynos_drm_hdmi shim and support mixer/hdmi & fimd/dp
> >> with common code.
> >>
> >> Signed-off-by: Sean Paul <seanpaul@chromium.org>
> >> ---
> >>
> >> Changes in v2:
> >>       - Pass display into display_ops instead of context
> >
> > Sorry but it seems like more reasonable to pass device object into
> > display_ops and manager_ops.
> >
> 
> 
> So you've changed your mind from when you said the following?
> 
> >>> manager->ops->xxx(manager, ...);
> >>> display->ops->xxx(display, ...);
> >>>
> >>> Agree.
> 


True. Before that, My comment was to pass device object into display_ops and
manager_ops, and then you said the good solution is to pass manager and
display to each driver. At that time, I thought no matter how the callback
is called if the framework doesn't call callbacks of each driver with ctx.
So I agreed.


> It would have been nice if you had changed your mind *before* I
> reworked everything. At any rate, I think it's still the right thing
> to do.

Really sorry about that. And I will add new patch for it so you don't need
to concern about that.

> 
> 
> > I'm not sure but display_ops could be implemented in other framework
> based
> > driver such as CDF based lcd panel driver. So if you pass display - it's
> > specific to exynos drm framework - into display_ops, the other framework
> > based driver should include specific exynos drm header.
> >
> 
> AFAIK, CDF will not land in its current separate-from-drm form, we
> don't need to worry about this. Furthermore, these ops should just go
> away and become drm_crtc/drm_encoder/drm_connector funcs anyways.
> 

Can you assure the display_ops never implemented in other framework based
driver, not CDF? At any rate, I think all possibilities should be opened.

> 
> > And another one, the patch 6 passes manager object to manager_ops, and
> for
> > this, you made the manager object to be set to driver data;
> > platform_set_drvdata(pdev, &manager). That isn't reasonable. Generally,
> > driver_data would point to device driver's context object.
> >
> 
> I'm not sure why this isn't reasonable, but it's a moot point. The
> driver data is only used up until we get rid of the pm ops, it needn't
> be set at all once things go through dpms.
> 

Generally, device drivers can call its own internal functions, and they will
call that functions with ctx. However, if you set manager to driver_data
then that functions should be called with manager object and also internally
that functions should get ctx from the manager object. What is the purpose
of manager? Do you think it's reasonable?

Anyway, I'd like to say really sorry about inconvenient again. So I will fix
it. 

Thanks,
Inki Dae

> Sean
> 
> 
> > Thanks,
> > Inki Dae
> >