[Intel-gfx] [PATCH] drm/i915: Probe system memory regions before enabling HW

[Chris Wilson]

Quoting Matthew Auld (2021-02-11 12:27:56)
> On 11/02/2021 11:20, Chris Wilson wrote:
> > If we want to track system/stolen as memory regions, we need to setup
> > our bookkeeping *before* we want to start allocating and reserving
> > objects in those regions. In particular, in setup up the GGTT we will
> > try to preallocate stolen regions configured by the BIOS, and so should
> > prepare the system-stolen memory region beforehand.
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Matthew Auld <matthew.auld at intel.com>
> > ---
> >   drivers/gpu/drm/i915/i915_drv.c | 8 ++++----
> >   1 file changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> > index b708517d3972..139cea4443fd 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.c
> > +++ b/drivers/gpu/drm/i915/i915_drv.c
> > @@ -557,6 +557,10 @@ static int i915_driver_hw_probe(struct drm_i915_private *dev_priv)
> >   
> >       i915_perf_init(dev_priv);
> >   
> > +     ret = intel_memory_regions_hw_probe(dev_priv);
> > +     if (ret)
> > +             goto err_ggtt;
> 
> Hmmm, adjust_stolen is also peeking at ggtt_total_entries(ggtt) on some 
> old platforms.

A nice catch-22. More splitting required. Maybe a fixup pass from
init_ggtt would work best.
-Chris