[Intel-gfx] [PATCH] [v5] drm/i915/bdw: Only use 2g GGTT for 32b platforms

[Daniel Vetter]

On Tue, Jun 03, 2014 at 06:05:45AM +0000, Yang, Guang A wrote:
> Tested-by: "Yang, Guang A" <guang.a.yang at intel.com>
> With this patch, the 32 bit system can be able to boot normally.

I wonder what's going to happen on 64 bit kernels with 32 bit userspace.
Since that one's a really common thing with games. Whatever. Queued for
-next, thanks for the patch.
-Daniel
> 
> 
> 
> Best Regards~~
> 
> Open Source Technology Center (OTC)
> Terence Yang（杨光）
> Tel: 86-021-61167360
> iNet: 8821-7360
> 
> > -----Original Message-----
> > From: Intel-gfx [mailto:intel-gfx-bounces at lists.freedesktop.org] On Behalf Of
> > Ben Widawsky
> > Sent: Wednesday, May 28, 2014 7:53 AM
> > To: Intel GFX
> > Cc: Ben Widawsky; stable at vger.kernel.org; Widawsky, Benjamin
> > Subject: [Intel-gfx] [PATCH] [v5] drm/i915/bdw: Only use 2g GGTT for 32b
> > platforms
> > 
> > Daniel requested in the bug that I use a 3GB fallback size. Since this is not in
> > the spec as a valid size, I decided against it. We could potentially add a patch to
> > bump it to 3GB on top of this one.
> > 
> > This probably should be CC: stable - but I'll let the powers that be decide that
> > one.
> > 
> > Regression from a revert of the revert:
> > commit 7907f45bf9f67a1c5e5d4ae05bab428d7c2f43b2
> > Author: Ben Widawsky <benjamin.widawsky at intel.com>
> > Date:   Wed Feb 19 22:05:46 2014 -0800
> > 
> >     Revert "drm/i915/bdw: Limit GTT to 2GB"
> > 
> > v2: Change ifdef to 32b, instead of ifndef update comment
> > 
> > v3. Update comment to not wrap (Daniel).
> > Update commit message
> > 
> > v4: s/CONFIG_32/CONFIG_X86_32 (Jani).
> > 
> > v5: s/CONFIG_x86_32BIT/CONFIG_x86_32, as meant in v4 s/32B/32b (chris)
> > 
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76619
> > Cc: stable at vger.kernel.org
> > Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> > Signed-off-by: Rodrigo Vivi <rodrigo.vivi at gmail.com>
> > Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> > ---
> >  drivers/gpu/drm/i915/i915_gem_gtt.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > index 931b906..eec820a 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > @@ -1775,6 +1775,13 @@ static inline unsigned int
> > gen8_get_total_gtt_size(u16 bdw_gmch_ctl)
> >  	bdw_gmch_ctl &= BDW_GMCH_GGMS_MASK;
> >  	if (bdw_gmch_ctl)
> >  		bdw_gmch_ctl = 1 << bdw_gmch_ctl;
> > +
> > +#ifdef CONFIG_X86_32
> > +	/* Limit 32b platforms to a 2GB GGTT: 4 << 20 / pte size * PAGE_SIZE */
> > +	if (bdw_gmch_ctl > 4)
> > +		bdw_gmch_ctl = 4;
> > +#endif
> > +
> >  	return bdw_gmch_ctl << 20;
> >  }
> > 
> > --
> > 1.9.3
> > 
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> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch