[PATCH] drm/i915: Move Braswell stop_machine GGTT insertion workaround

[PATCH] drm/i915: Move Braswell stop_machine GGTT insertion workaround

[Chris Wilson]

There was a silent conflict between

commit 0a878716265e9af9f697264dc2e858fcc060d833
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Oct 15 14:23:01 2015 +0200

    drm/i915: restore ggtt double-bind avoidance

and

commit 5bab6f60cb4d1417ad7c599166bcfec87529c1a2
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Fri Oct 23 18:43:32 2015 +0100

    drm/i915: Serialise updates to GGTT with access through GGTT on Braswell

thankfully caught by the extra WARN safegaurd in 0a878716. Since we now
override the GGTT insert_pages callback when installing the aliasing
ppgtt, we assert that the callback is the original ggtt routine.
However, on Braswell we now use a different insertion routine to
serialise access through the GGTT with updating the PTE and hence the
conflict. To avoid the conflict, move the custom insertion routine for
Braswell down a level.

Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 50 +++++++++++++++++++++----------------
 1 file changed, 28 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 4d357e18e5d1..8cd271fa2396 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -2386,6 +2386,32 @@ static void gen8_ggtt_insert_entries(struct i915_address_space *vm,
 	POSTING_READ(GFX_FLSH_CNTL_GEN6);
 }
 
+struct insert_entries {
+	struct i915_address_space *vm;
+	struct sg_table *st;
+	uint64_t start;
+	enum i915_cache_level level;
+	u32 flags;
+};
+
+static int gen8_ggtt_insert_entries__cb(void *_arg)
+{
+	struct insert_entries *arg = _arg;
+	gen8_ggtt_insert_entries(arg->vm, arg->st,
+				 arg->start, arg->level, arg->flags);
+	return 0;
+}
+
+static void gen8_ggtt_insert_entries__BKL(struct i915_address_space *vm,
+					  struct sg_table *st,
+					  uint64_t start,
+					  enum i915_cache_level level,
+					  u32 flags)
+{
+	struct insert_entries arg = { vm, st, start, level, flags };
+	stop_machine(gen8_ggtt_insert_entries__cb, &arg, NULL);
+}
+
 /*
  * Binds an object into the global gtt with the specified cache level. The object
  * will be accessible to the GPU via commands whose operands reference offsets
@@ -2534,26 +2560,6 @@ static int ggtt_bind_vma(struct i915_vma *vma,
 	return 0;
 }
 
-struct ggtt_bind_vma__cb {
-	struct i915_vma *vma;
-	enum i915_cache_level cache_level;
-	u32 flags;
-};
-
-static int ggtt_bind_vma__cb(void *_arg)
-{
-	struct ggtt_bind_vma__cb *arg = _arg;
-	return ggtt_bind_vma(arg->vma, arg->cache_level, arg->flags);
-}
-
-static int ggtt_bind_vma__BKL(struct i915_vma *vma,
-			      enum i915_cache_level cache_level,
-			      u32 flags)
-{
-	struct ggtt_bind_vma__cb arg = { vma, cache_level, flags };
-	return stop_machine(ggtt_bind_vma__cb, &arg, NULL);
-}
-
 static int aliasing_gtt_bind_vma(struct i915_vma *vma,
 				 enum i915_cache_level cache_level,
 				 u32 flags)
@@ -3021,8 +3027,8 @@ static int gen8_gmch_probe(struct drm_device *dev,
 	dev_priv->gtt.base.bind_vma = ggtt_bind_vma;
 	dev_priv->gtt.base.unbind_vma = ggtt_unbind_vma;
 
-	if (IS_CHERRYVIEW(dev))
-		dev_priv->gtt.base.bind_vma = ggtt_bind_vma__BKL;
+	if (IS_CHERRYVIEW(dev_priv))
+		dev_priv->gtt.base.insert_entries = gen8_ggtt_insert_entries__BKL;
 
 	return ret;
 }
-- 
2.6.2

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Re: [PATCH] drm/i915: Move Braswell stop_machine GGTT insertion workaround

[Ville Syrjälä]

On Wed, Nov 18, 2015 at 03:19:39PM +0000, Chris Wilson wrote:
> There was a silent conflict between
> 
> commit 0a878716265e9af9f697264dc2e858fcc060d833
> Author: Daniel Vetter <daniel.vetter@ffwll.ch>
> Date:   Thu Oct 15 14:23:01 2015 +0200
> 
>     drm/i915: restore ggtt double-bind avoidance
> 
> and
> 
> commit 5bab6f60cb4d1417ad7c599166bcfec87529c1a2
> Author: Chris Wilson <chris@chris-wilson.co.uk>
> Date:   Fri Oct 23 18:43:32 2015 +0100
> 
>     drm/i915: Serialise updates to GGTT with access through GGTT on Braswell
> 
> thankfully caught by the extra WARN safegaurd in 0a878716. Since we now
> override the GGTT insert_pages callback when installing the aliasing
> ppgtt, we assert that the callback is the original ggtt routine.
> However, on Braswell we now use a different insertion routine to
> serialise access through the GGTT with updating the PTE and hence the
> conflict. To avoid the conflict, move the custom insertion routine for
> Braswell down a level.
> 
> Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Michel Thierry <michel.thierry@intel.com>
> Cc: Mika Kuoppala <mika.kuoppala@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem_gtt.c | 50 +++++++++++++++++++++----------------
>  1 file changed, 28 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 4d357e18e5d1..8cd271fa2396 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -2386,6 +2386,32 @@ static void gen8_ggtt_insert_entries(struct i915_address_space *vm,
>  	POSTING_READ(GFX_FLSH_CNTL_GEN6);
>  }
>  
> +struct insert_entries {
> +	struct i915_address_space *vm;
> +	struct sg_table *st;
> +	uint64_t start;
> +	enum i915_cache_level level;
> +	u32 flags;
> +};
> +
> +static int gen8_ggtt_insert_entries__cb(void *_arg)
> +{
> +	struct insert_entries *arg = _arg;
> +	gen8_ggtt_insert_entries(arg->vm, arg->st,
> +				 arg->start, arg->level, arg->flags);
> +	return 0;
> +}
> +
> +static void gen8_ggtt_insert_entries__BKL(struct i915_address_space *vm,
> +					  struct sg_table *st,
> +					  uint64_t start,
> +					  enum i915_cache_level level,
> +					  u32 flags)
> +{
> +	struct insert_entries arg = { vm, st, start, level, flags };

Could use named initializers to avoid potential accidents with the
weaker typed members. But the struct definition is close by so not a
huge risk.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> +	stop_machine(gen8_ggtt_insert_entries__cb, &arg, NULL);
> +}
> +
>  /*
>   * Binds an object into the global gtt with the specified cache level. The object
>   * will be accessible to the GPU via commands whose operands reference offsets
> @@ -2534,26 +2560,6 @@ static int ggtt_bind_vma(struct i915_vma *vma,
>  	return 0;
>  }
>  
> -struct ggtt_bind_vma__cb {
> -	struct i915_vma *vma;
> -	enum i915_cache_level cache_level;
> -	u32 flags;
> -};
> -
> -static int ggtt_bind_vma__cb(void *_arg)
> -{
> -	struct ggtt_bind_vma__cb *arg = _arg;
> -	return ggtt_bind_vma(arg->vma, arg->cache_level, arg->flags);
> -}
> -
> -static int ggtt_bind_vma__BKL(struct i915_vma *vma,
> -			      enum i915_cache_level cache_level,
> -			      u32 flags)
> -{
> -	struct ggtt_bind_vma__cb arg = { vma, cache_level, flags };
> -	return stop_machine(ggtt_bind_vma__cb, &arg, NULL);
> -}
> -
>  static int aliasing_gtt_bind_vma(struct i915_vma *vma,
>  				 enum i915_cache_level cache_level,
>  				 u32 flags)
> @@ -3021,8 +3027,8 @@ static int gen8_gmch_probe(struct drm_device *dev,
>  	dev_priv->gtt.base.bind_vma = ggtt_bind_vma;
>  	dev_priv->gtt.base.unbind_vma = ggtt_unbind_vma;
>  
> -	if (IS_CHERRYVIEW(dev))
> -		dev_priv->gtt.base.bind_vma = ggtt_bind_vma__BKL;
> +	if (IS_CHERRYVIEW(dev_priv))
> +		dev_priv->gtt.base.insert_entries = gen8_ggtt_insert_entries__BKL;
>  
>  	return ret;
>  }
> -- 
> 2.6.2

-- 
Ville Syrjälä
Intel OTC
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Re: [PATCH] drm/i915: Move Braswell stop_machine GGTT insertion workaround

[Chris Wilson]

On Wed, Dec 16, 2015 at 10:02:29PM +0200, Ville Syrjälä wrote:
> On Wed, Nov 18, 2015 at 03:19:39PM +0000, Chris Wilson wrote:
> > +static void gen8_ggtt_insert_entries__BKL(struct i915_address_space *vm,
> > +					  struct sg_table *st,
> > +					  uint64_t start,
> > +					  enum i915_cache_level level,
> > +					  u32 flags)
> > +{
> > +	struct insert_entries arg = { vm, st, start, level, flags };
> 
> Could use named initializers to avoid potential accidents with the
> weaker typed members. But the struct definition is close by so not a
> huge risk.

struct insert_entries arg = { .vm=vm, .st=st, .start=start, .level=level, .flags=flags };

Hmm, I may just pass on that for the moment.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre
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Re: [PATCH] drm/i915: Move Braswell stop_machine GGTT insertion workaround

[Daniel Vetter]

On Wed, Dec 16, 2015 at 10:02:29PM +0200, Ville Syrjälä wrote:
> On Wed, Nov 18, 2015 at 03:19:39PM +0000, Chris Wilson wrote:
> > There was a silent conflict between
> > 
> > commit 0a878716265e9af9f697264dc2e858fcc060d833
> > Author: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Date:   Thu Oct 15 14:23:01 2015 +0200
> > 
> >     drm/i915: restore ggtt double-bind avoidance
> > 
> > and
> > 
> > commit 5bab6f60cb4d1417ad7c599166bcfec87529c1a2
> > Author: Chris Wilson <chris@chris-wilson.co.uk>
> > Date:   Fri Oct 23 18:43:32 2015 +0100
> > 
> >     drm/i915: Serialise updates to GGTT with access through GGTT on Braswell
> > 
> > thankfully caught by the extra WARN safegaurd in 0a878716. Since we now
> > override the GGTT insert_pages callback when installing the aliasing
> > ppgtt, we assert that the callback is the original ggtt routine.
> > However, on Braswell we now use a different insertion routine to
> > serialise access through the GGTT with updating the PTE and hence the
> > conflict. To avoid the conflict, move the custom insertion routine for
> > Braswell down a level.
> > 
> > Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com
> > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com
> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Cc: Michel Thierry <michel.thierry@intel.com>
> > Cc: Mika Kuoppala <mika.kuoppala@intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_gem_gtt.c | 50 +++++++++++++++++++++----------------
> >  1 file changed, 28 insertions(+), 22 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > index 4d357e18e5d1..8cd271fa2396 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > @@ -2386,6 +2386,32 @@ static void gen8_ggtt_insert_entries(struct i915_address_space *vm,
> >  	POSTING_READ(GFX_FLSH_CNTL_GEN6);
> >  }
> >  
> > +struct insert_entries {
> > +	struct i915_address_space *vm;
> > +	struct sg_table *st;
> > +	uint64_t start;
> > +	enum i915_cache_level level;
> > +	u32 flags;
> > +};
> > +
> > +static int gen8_ggtt_insert_entries__cb(void *_arg)
> > +{
> > +	struct insert_entries *arg = _arg;
> > +	gen8_ggtt_insert_entries(arg->vm, arg->st,
> > +				 arg->start, arg->level, arg->flags);
> > +	return 0;
> > +}
> > +
> > +static void gen8_ggtt_insert_entries__BKL(struct i915_address_space *vm,
> > +					  struct sg_table *st,
> > +					  uint64_t start,
> > +					  enum i915_cache_level level,
> > +					  u32 flags)
> > +{
> > +	struct insert_entries arg = { vm, st, start, level, flags };
> 
> Could use named initializers to avoid potential accidents with the
> weaker typed members. But the struct definition is close by so not a
> huge risk.
> 
> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Queued for -next (including cc: fixes), thanks for the patch.
-Daniel

> 
> > +	stop_machine(gen8_ggtt_insert_entries__cb, &arg, NULL);
> > +}
> > +
> >  /*
> >   * Binds an object into the global gtt with the specified cache level. The object
> >   * will be accessible to the GPU via commands whose operands reference offsets
> > @@ -2534,26 +2560,6 @@ static int ggtt_bind_vma(struct i915_vma *vma,
> >  	return 0;
> >  }
> >  
> > -struct ggtt_bind_vma__cb {
> > -	struct i915_vma *vma;
> > -	enum i915_cache_level cache_level;
> > -	u32 flags;
> > -};
> > -
> > -static int ggtt_bind_vma__cb(void *_arg)
> > -{
> > -	struct ggtt_bind_vma__cb *arg = _arg;
> > -	return ggtt_bind_vma(arg->vma, arg->cache_level, arg->flags);
> > -}
> > -
> > -static int ggtt_bind_vma__BKL(struct i915_vma *vma,
> > -			      enum i915_cache_level cache_level,
> > -			      u32 flags)
> > -{
> > -	struct ggtt_bind_vma__cb arg = { vma, cache_level, flags };
> > -	return stop_machine(ggtt_bind_vma__cb, &arg, NULL);
> > -}
> > -
> >  static int aliasing_gtt_bind_vma(struct i915_vma *vma,
> >  				 enum i915_cache_level cache_level,
> >  				 u32 flags)
> > @@ -3021,8 +3027,8 @@ static int gen8_gmch_probe(struct drm_device *dev,
> >  	dev_priv->gtt.base.bind_vma = ggtt_bind_vma;
> >  	dev_priv->gtt.base.unbind_vma = ggtt_unbind_vma;
> >  
> > -	if (IS_CHERRYVIEW(dev))
> > -		dev_priv->gtt.base.bind_vma = ggtt_bind_vma__BKL;
> > +	if (IS_CHERRYVIEW(dev_priv))
> > +		dev_priv->gtt.base.insert_entries = gen8_ggtt_insert_entries__BKL;
> >  
> >  	return ret;
> >  }
> > -- 
> > 2.6.2
> 
> -- 
> Ville Syrjälä
> Intel OTC

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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