drm/i915: Simplify flush_cpu_write_domain
We can push down the decision whether to force flushing into the
implementation since in all places that matter obj->pin_display is
accurate already. The only place where the optimization really matters
is the sw_finish_ioctl, and that already checks for obj->pin_display
on its own.
I suspect that this was simply an artifact of how
commit 2c22569bba8af6c2976d5f9479fe54a53a39966b
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Fri Aug 9 12:26:45 2013 +0100
drm/i915: Update rules for writing through the LLC with the cpu
evolved - only v2 added the pin_display tracking.
Note that we still retain the gist of this logic from the above commit
with the explicit force argument for the low-level clflush function.
Ville noted in his review that there's a slight behavioural change in
the set_to_gtt_domain function, which now also will flush display
plane data. This opens-open the potential for userspace to start doing
buggy things by omitting the sw_finish_ioctl, which is why I've
rejected a functional equivalent patch from Ville a while ago:
http://lists.freedesktop.org/archives/intel-gfx/2013-November/036421.html
But on second consideration it's not that evil, and in any case the
justification here is more clarity, not allowing crazy userspace.
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index a0264aa..9c7c95a 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -39,8 +39,7 @@
#include <linux/dma-buf.h>
static void i915_gem_object_flush_gtt_write_domain(struct drm_i915_gem_object *obj);
-static void i915_gem_object_flush_cpu_write_domain(struct drm_i915_gem_object *obj,
- bool force);
+static void i915_gem_object_flush_cpu_write_domain(struct drm_i915_gem_object *obj);
static __must_check int
i915_gem_object_wait_rendering(struct drm_i915_gem_object *obj,
bool readonly);
@@ -1516,7 +1515,7 @@
/* Pinned buffers may be scanout, so flush the cache */
if (obj->pin_display)
- i915_gem_object_flush_cpu_write_domain(obj, true);
+ i915_gem_object_flush_cpu_write_domain(obj);
drm_gem_object_unreference(&obj->base);
unlock:
@@ -3680,15 +3679,14 @@
/** Flushes the CPU write domain for the object if it's dirty. */
static void
-i915_gem_object_flush_cpu_write_domain(struct drm_i915_gem_object *obj,
- bool force)
+i915_gem_object_flush_cpu_write_domain(struct drm_i915_gem_object *obj)
{
uint32_t old_write_domain;
if (obj->base.write_domain != I915_GEM_DOMAIN_CPU)
return;
- if (i915_gem_clflush_object(obj, force))
+ if (i915_gem_clflush_object(obj, obj->pin_display))
i915_gem_chipset_flush(obj->base.dev);
old_write_domain = obj->base.write_domain;
@@ -3735,7 +3733,7 @@
if (ret)
return ret;
- i915_gem_object_flush_cpu_write_domain(obj, false);
+ i915_gem_object_flush_cpu_write_domain(obj);
/* Serialise direct access to this object with the barriers for
* coherent writes from the GPU, by effectively invalidating the
@@ -3981,7 +3979,7 @@
if (ret)
goto err_unpin_display;
- i915_gem_object_flush_cpu_write_domain(obj, true);
+ i915_gem_object_flush_cpu_write_domain(obj);
old_write_domain = obj->base.write_domain;
old_read_domains = obj->base.read_domains;