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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2018-07-20 13:19:10 +0300 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2018-07-20 18:53:55 +0300 |
| commit | 900ccf30f9e112b508a61b228bf014e3bea14bc4 (patch) | |
| tree | 46c7ba2f992813bc80aeee8c476eac9816b6b93d /drivers/gpu/drm/i915/i915_drv.c | |
| parent | 35e900818e177d9ae34988d15461792582937924 (diff) | |
| download | linux-900ccf30f9e112b508a61b228bf014e3bea14bc4.tar.xz | |
drm/i915: Only force GGTT coherency w/a on required chipsets
Not all chipsets have an internal buffer delaying the visibility of
writes via the GGTT being visible by other physical paths, but we use a
very heavy workaround for all. We only need to apply that workarounds to
the chipsets we know suffer from the delay and the resulting coherency
issue.
Similarly, the same inconsistent coherency fouls up our ABI promise that
a write into a mmap_gtt is immediately visible to others. Since the HW
has made that a lie, let userspace know when that contract is broken.
(Not that userspace would want to use mmap_gtt on those chipsets for
other performance reasons...)
Testcase: igt/drv_selftest/live_coherency
Testcase: igt/gem_mmap_gtt/coherency
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100587
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Tomasz Lis <tomasz.lis@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180720101910.11153-1-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm/i915/i915_drv.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_drv.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index 343e79a44abd..23e9a86cbc2a 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -441,6 +441,9 @@ static int i915_getparam_ioctl(struct drm_device *dev, void *data, case I915_PARAM_CS_TIMESTAMP_FREQUENCY: value = 1000 * INTEL_INFO(dev_priv)->cs_timestamp_frequency_khz; break; + case I915_PARAM_MMAP_GTT_COHERENT: + value = INTEL_INFO(dev_priv)->has_coherent_ggtt; + break; default: DRM_DEBUG("Unknown parameter %d\n", param->param); return -EINVAL; |