[Intel-gfx] [PATCH 04/14] drm/i915/tgl: Fix driver crash when update_active_dpll is called

[Souza, Jose]

On Fri, 2019-09-13 at 23:32 -0700, Lucas De Marchi wrote:
> On Fri, Sep 13, 2019 at 3:33 PM José Roberto de Souza
> <jose.souza at intel.com> wrote:
> > From: "Taylor, Clinton A" <clinton.a.taylor at intel.com>
> > 
> > TGL PLL function table doesn't include and update_active_pll
> > function.
> > The driver attempts to make a call to this function and crashes
> > during
> > PLL changes.
> 
> the crash would only occur if the port was initialized. The ordering
> in this series means this is
> not a "fix" but rather finishing the implementation for TC ports
> before initializing them. So we may
> want to adjust the commit message accordingly. The reason we missed
> that for TGL is that its need came
> in parallel to the TGL support hitting upstream.
> 

Okay will change commit message and description to:

drm/i915/tgl/pll: Set update_active_dpll

Commit 24a7bfe0c2d7 ("drm/i915: Keep the TypeC port mode fixed when the
port is active") added this new hook while in parallel TGL upstream was
happening and this was missed.
Without this driver will crash when TC DDI is added and driver is
preparing to do a full modeset.

Sounds good?


> My nit with this hook is that `update_active_dpll` is exclusively
> used
> by *TC* ports on gen 11+ and
> a) it's  not clear about that from the name and/or b) if it's generic
> it should not crash when it's missing.
> 
> I think Imre had a patch to address it, at least renaming the hook, I
> don't remember. +Imre.

Well we can do that on top or in Imre series not planing to address
this in here.

> 
> Lucas De Marchi

@Clint

Looks like git send-email don't like "," in the name and replaces your
email address to Taylor at freedesktop.org so I'm going to replace your
signed-off-by to "Clinton A Taylor <clinton.a.taylor at intel.com>" or do
you prefer something else?

> 
> > Signed-off-by: Taylor, Clinton A <clinton.a.taylor at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_dpll_mgr.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
> > b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
> > index 98288edf88f0..84e734d44828 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
> > @@ -3479,6 +3479,7 @@ static const struct intel_dpll_mgr
> > tgl_pll_mgr = {
> >         .dpll_info = tgl_plls,
> >         .get_dplls = icl_get_dplls,
> >         .put_dplls = icl_put_dplls,
> > +       .update_active_dpll = icl_update_active_dpll,
> >         .dump_hw_state = icl_dump_hw_state,
> >  };
> > 
> > --
> > 2.23.0
> > 
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> 
>