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From: Matthew Auld <matthew.auld@intel.com>
To: intel-gfx@lists.freedesktop.org
Cc: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>,
	dri-devel@lists.freedesktop.org,
	"Gwan-gyeong Mun" <gwan-gyeong.mun@intel.com>
Subject: [PATCH] drm/i915: tweak the ordering in cpu_write_needs_clflush
Date: Wed, 22 Jun 2022 16:59:19 +0100	[thread overview]
Message-ID: <20220622155919.355081-1-matthew.auld@intel.com> (raw)

For imported dma-buf objects we leave the object as cache_coherent = 0
across all platforms, which is reasonable given that have no clue what
the memory underneath is, and its not like the driver can ever manually
clflush the pages anyway (like with i915_gem_clflush_object) for such
objects. However on discrete we choose to treat cache_dirty = true as a
programmer error, leading to a warning. The simplest fix looks to be to
just change the ordering in cpu_write_needs_clflush to prevent ever
setting cache_dirty for dma-buf objects on discrete.

Fixes: d028a7690d87 ("drm/i915/dmabuf: Fix prime_mmap to work when using LMEM")
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/5266
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_domain.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_domain.c b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
index 3e5d6057b3ef..1674b0c5802b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
@@ -35,12 +35,12 @@ bool i915_gem_cpu_write_needs_clflush(struct drm_i915_gem_object *obj)
 	if (obj->cache_dirty)
 		return false;
 
-	if (!(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE))
-		return true;
-
 	if (IS_DGFX(i915))
 		return false;
 
+	if (!(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE))
+		return true;
+
 	/* Currently in use by HW (display engine)? Keep flushed. */
 	return i915_gem_object_is_framebuffer(obj);
 }
-- 
2.36.1


WARNING: multiple messages have this Message-ID (diff)
From: Matthew Auld <matthew.auld@intel.com>
To: intel-gfx@lists.freedesktop.org
Cc: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>,
	dri-devel@lists.freedesktop.org
Subject: [Intel-gfx] [PATCH] drm/i915: tweak the ordering in cpu_write_needs_clflush
Date: Wed, 22 Jun 2022 16:59:19 +0100	[thread overview]
Message-ID: <20220622155919.355081-1-matthew.auld@intel.com> (raw)

For imported dma-buf objects we leave the object as cache_coherent = 0
across all platforms, which is reasonable given that have no clue what
the memory underneath is, and its not like the driver can ever manually
clflush the pages anyway (like with i915_gem_clflush_object) for such
objects. However on discrete we choose to treat cache_dirty = true as a
programmer error, leading to a warning. The simplest fix looks to be to
just change the ordering in cpu_write_needs_clflush to prevent ever
setting cache_dirty for dma-buf objects on discrete.

Fixes: d028a7690d87 ("drm/i915/dmabuf: Fix prime_mmap to work when using LMEM")
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/5266
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_domain.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_domain.c b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
index 3e5d6057b3ef..1674b0c5802b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
@@ -35,12 +35,12 @@ bool i915_gem_cpu_write_needs_clflush(struct drm_i915_gem_object *obj)
 	if (obj->cache_dirty)
 		return false;
 
-	if (!(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE))
-		return true;
-
 	if (IS_DGFX(i915))
 		return false;
 
+	if (!(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE))
+		return true;
+
 	/* Currently in use by HW (display engine)? Keep flushed. */
 	return i915_gem_object_is_framebuffer(obj);
 }
-- 
2.36.1


             reply	other threads:[~2022-06-22 15:59 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-22 15:59 Matthew Auld [this message]
2022-06-22 15:59 ` [Intel-gfx] [PATCH] drm/i915: tweak the ordering in cpu_write_needs_clflush Matthew Auld
2022-06-23  0:38 ` [Intel-gfx] ✓ Fi.CI.BAT: success for " Patchwork
2022-06-27  7:43 ` [PATCH] " Gwan-gyeong Mun
2022-06-27  7:43   ` [Intel-gfx] " Gwan-gyeong Mun
2022-06-27 11:49 ` [Intel-gfx] ✗ Fi.CI.IGT: failure for " Patchwork
2022-06-27 12:03   ` Matthew Auld
2022-06-27 17:51     ` Vudum, Lakshminarayana
2022-06-28  0:08 ` [Intel-gfx] ✓ Fi.CI.IGT: success " Patchwork

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