Re: [PATCH] drm/i915: Report amount of usable graphics memory in MiB

[Ben Widawsky <ben@bwidawsk.net>]

On Sun, 11 Nov 2012 18:48:55 +0100
Daniel Vetter <daniel@ffwll.ch> wrote:

> On Sun, Nov 11, 2012 at 09:34:06AM -0800, Ben Widawsky wrote:
> > On Sun, 11 Nov 2012 09:34:45 +0000
> > Chris Wilson <chris@chris-wilson.co.uk> wrote:
> > 
> > > ...rather than kilo-PTE.
> > > 
> > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> > > ---
> > >  drivers/gpu/drm/i915/i915_gem_gtt.c |    2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > > index e7515e8..938710a 100644
> > > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > > @@ -708,7 +708,7 @@ int i915_gem_gtt_init(struct drm_device *dev)
> > >  	}
> > >  
> > >  	/* GMADR is the PCI aperture used by SW to access tiled GFX surfaces in a linear fashion. */
> > > -	DRM_INFO("Memory Usable by graphics device = %dK\n", dev_priv->mm.gtt->gtt_total_entries >> 10);
> > > +	DRM_INFO("Memory Usable by graphics device = %dM\n", dev_priv->mm.gtt->gtt_total_entries >> 8);
> > >  	DRM_DEBUG_DRIVER("GMADR size = %dM\n", dev_priv->mm.gtt->gtt_mappable_entries >> 8);
> > >  	DRM_DEBUG_DRIVER("GTT stolen size = %dM\n", dev_priv->mm.gtt->stolen_size >> 20);
> > >  
> > 
> > Shouldn't it be >> 18 though, not >> 8?
> 
> Each pte entry stands for a 4k page, so entries is already size >> 12, so
> we only need to shift by 8 to get M. Patch merged to dinq.
> -Daniel

Looking through the code it didn't seem to match what you're saying,
but I do agree, it's ((total entries << 12)) >> 20) which is total
entries >> 8. I've verified it too on my machine. I'll blame it on a
lack of caffeine.

Please make "usable" lower case while you're at it.