From 2074ff710f27863e84798cc18952a99f2b379b7c Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon, 12 Aug 2013 11:46:17 +0100
Subject: [PATCH] drm/i915: Drop the overzealous warning from
i915_gem_set_cache_level
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By our earlier reckoning, move from a snooped/llc setting to an uncached
setting, leaves the CPU cache in a consistent state irrespective of our
domain tracking - so we can forgo the warning about the lack of
invalidation. Similarly for any writes posted to the snooped CPU domain,
we know will be safely clflushed to the uncached PTEs after forcing the
domain change.
This WARN started to pop up with
commit b58f8be8b44b2c3773f85dab1b85195940f0d9fc
Author: Chris Wilson <chris@chris-wilson.co.uk>
AuthorDate: Thu Aug 8 14:41:06 2013 +0100
drm/i915: Allow the GPU to cache stolen memory
Ville brought up a scenario where the interaction of a set_caching
ioctl call from userspace on a scanout buffer (i.e. obj->pin_display
is set) resulted in the code getting confused and not properly
flushing stale cpu cachelines. Luckily we already prevent this by
rejecting caching changes when obj->pin_count is set.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=68040
Tested-by: cancan,feng <cancan.feng@intel.com>
[danvet: Add buglink, bisect result and explain why Ville's scenario
is already taken care of.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
drivers/gpu/drm/i915/i915_gem.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index fd4872497a722..41dc042935846 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3440,7 +3440,6 @@ int i915_gem_object_set_cache_level(struct drm_i915_gem_object *obj,
* Just set it to the CPU cache for now.
*/
WARN_ON(obj->base.write_domain & ~I915_GEM_DOMAIN_CPU);
- WARN_ON(obj->base.read_domains & ~I915_GEM_DOMAIN_CPU);
old_read_domains = obj->base.read_domains;
old_write_domain = obj->base.write_domain;
--
2.39.5