diff options
author | Chris Wilson <chris@chris-wilson.co.uk> | 2017-08-11 14:11:16 +0300 |
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committer | Chris Wilson <chris@chris-wilson.co.uk> | 2017-08-15 17:46:57 +0300 |
commit | b8f55be64453ea77fc51bff6cd0d906d18ce1cd2 (patch) | |
tree | 4027cbcc167720619217458cf7a7213913f6dc81 /drivers/gpu/drm/i915/i915_gem_execbuffer.c | |
parent | 9c3a16c887f0f8f62813d841f028eabc153581f3 (diff) | |
download | linux-b8f55be64453ea77fc51bff6cd0d906d18ce1cd2.tar.xz |
drm/i915: Split obj->cache_coherent to track r/w
Another month, another story in the cache coherency saga. This time, we
come to the realisation that i915_gem_object_is_coherent() has been
reporting whether we can read from the target without requiring a cache
invalidate; but we were using it in places for testing whether we could
write into the object without requiring a cache flush. So split the
tracking into two, one to decide before reads, one after writes.
See commit e27ab73d17ef ("drm/i915: Mark CPU cache as dirty on every
transition for CPU writes") for the previous entry in this saga.
v2: Be verbose
v3: Remove unused function (i915_gem_object_is_coherent)
v4: Fix inverted coherency check prior to execbuf (from v2)
v5: Add comment for nasty code where we are optimising on gcc's behalf.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101109
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101555
Testcase: igt/kms_mmap_write_crc
Testcase: igt/kms_pwrite_crc
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Tested-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170811111116.10373-1-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Diffstat (limited to 'drivers/gpu/drm/i915/i915_gem_execbuffer.c')
-rw-r--r-- | drivers/gpu/drm/i915/i915_gem_execbuffer.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c index 5fa44767c29e..99520b2fac7c 100644 --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c @@ -1842,7 +1842,19 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb) eb->request->capture_list = capture; } - if (unlikely(obj->cache_dirty && !obj->cache_coherent)) { + /* + * If the GPU is not _reading_ through the CPU cache, we need + * to make sure that any writes (both previous GPU writes from + * before a change in snooping levels and normal CPU writes) + * caught in that cache are flushed to main memory. + * + * We want to say + * obj->cache_dirty && + * !(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_READ) + * but gcc's optimiser doesn't handle that as well and emits + * two jumps instead of one. Maybe one day... + */ + if (unlikely(obj->cache_dirty & ~obj->cache_coherent)) { if (i915_gem_clflush_object(obj, 0)) entry->flags &= ~EXEC_OBJECT_ASYNC; } |