Currently a tiled frame buffer to be scanned out is always installed
with a fence, leading to fence starvation on gen9lp virtualization
use case where graphics stacks of service and guest OSes compete for
fences.
By design, this fence is always needed by i965-(GEN4-) platforms.
For GEN4 and above, the fence is only required when the frame buffer
compression is enabled.
Changes are made to follow graphics hardware design principles.
Signed-off-by: Guang Bai <guang.bai@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_display.c | 44 +++++++++++++++++++++++++++---------
drivers/gpu/drm/i915/intel_drv.h | 4 +++-
drivers/gpu/drm/i915/intel_fbc.c | 2 +-
drivers/gpu/drm/i915/intel_fbdev.c | 3 ++-
4 files changed, 39 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 3dbf5ed..59004f5 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2068,7 +2068,8 @@ static unsigned int intel_surf_alignment(const struct drm_framebuffer *fb,
}
struct i915_vma *
-intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb, unsigned int rotation)
+intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb, unsigned int rotation,
+ struct drm_plane *plane, enum pipe pipe)
{
struct drm_device *dev = fb->dev;
struct drm_i915_private *dev_priv = to_i915(dev);
@@ -2076,6 +2077,8 @@ intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb, unsigned int rotation)
struct i915_ggtt_view view;
struct i915_vma *vma;
u32 alignment;
+ bool needs_fence = false;
+ struct intel_plane *intel_plane;
WARN_ON(!mutex_is_locked(&dev->struct_mutex));
@@ -2105,13 +2108,19 @@ intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb, unsigned int rotation)
vma = i915_gem_object_pin_to_display_plane(obj, alignment, &view);
if (IS_ERR(vma))
goto err;
+ /*
+ * Install the fence for pre-i965(GEN4-) tiled frame buffers all the
+ * time but only do it for i965(GEN4) and beyond when the frame buffer
+ * compression is enabled during boot up or runtime.
+ */
+ intel_plane = to_intel_plane(plane);
+ if (INTEL_GEN(dev_priv) < 4 || (intel_fbc_can_enable(dev_priv) &&
+ (pipe == PIPE_A) && intel_plane &&
+ (intel_plane->id == PLANE_PRIMARY)))
+ needs_fence = true;
if (i915_vma_is_map_and_fenceable(vma)) {
- /* Install a fence for tiled scan-out. Pre-i965 always needs a
- * fence, whereas 965+ only requires a fence if using
- * framebuffer compression. For simplicity, we always, when
- * possible, install a fence as the cost is not that onerous.
- *
+ /*
* If we fail to fence the tiled scanout, then either the
* modeset will reject the change (which is highly unlikely as
* the affected systems, all but one, do not have unmappable
@@ -2123,7 +2132,16 @@ intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb, unsigned int rotation)
* something and try to run the system in a "less than optimal"
* mode that matches the user configuration.
*/
- i915_vma_pin_fence(vma);
+ if (needs_fence)
+ i915_vma_pin_fence(vma);
+ else if (vma->fence)
+ /*
+ * For a reused fence, increase its ref count even if
+ * it's not pinned to maintain the count consistancy.
+ * This is because the count is unconditionally
+ * decreased when the fence is unpinned.
+ */
+ vma->fence->pin_count++;
}
i915_vma_get(vma);
@@ -2808,7 +2826,8 @@ intel_find_initial_plane_obj(struct intel_crtc *intel_crtc,
valid_fb:
mutex_lock(&dev->struct_mutex);
intel_state->vma =
- intel_pin_and_fence_fb_obj(fb, primary->state->rotation);
+ intel_pin_and_fence_fb_obj(fb, primary->state->rotation,
+ primary, intel_crtc->pipe);
mutex_unlock(&dev->struct_mutex);
if (IS_ERR(intel_state->vma)) {
DRM_ERROR("failed to pin boot fb on pipe %d: %li\n",
@@ -12711,8 +12730,9 @@ intel_prepare_plane_fb(struct drm_plane *plane,
ret = i915_gem_object_attach_phys(obj, align);
} else {
struct i915_vma *vma;
-
- vma = intel_pin_and_fence_fb_obj(fb, new_state->rotation);
+ struct intel_crtc *temp_crtc = to_intel_crtc(new_state->crtc);
+ vma = intel_pin_and_fence_fb_obj(fb, new_state->rotation,
+ plane, temp_crtc->pipe);
if (!IS_ERR(vma))
to_intel_plane_state(new_state)->vma = vma;
else
@@ -13128,7 +13148,9 @@ intel_legacy_cursor_update(struct drm_plane *plane,
goto out_unlock;
}
} else {
- vma = intel_pin_and_fence_fb_obj(fb, new_plane_state->rotation);
+ struct intel_crtc *temp_crtc = to_intel_crtc(crtc);
+ vma = intel_pin_and_fence_fb_obj(fb, new_plane_state->rotation,
+ plane, temp_crtc->pipe);
if (IS_ERR(vma)) {
DRM_DEBUG_KMS("failed to pin object\n");
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 898064e..7d98e069 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1503,7 +1503,8 @@ void intel_release_load_detect_pipe(struct drm_connector *connector,
struct intel_load_detect_pipe *old,
struct drm_modeset_acquire_ctx *ctx);
struct i915_vma *
-intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb, unsigned int rotation);
+intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb, unsigned int rotation,
+ struct drm_plane *plane, enum pipe pipe);
void intel_unpin_fb_vma(struct i915_vma *vma);
struct drm_framebuffer *
intel_framebuffer_create(struct drm_i915_gem_object *obj,
@@ -1759,6 +1760,7 @@ void intel_fbc_flush(struct drm_i915_private *dev_priv,
unsigned int frontbuffer_bits, enum fb_op_origin origin);
void intel_fbc_cleanup_cfb(struct drm_i915_private *dev_priv);
void intel_fbc_handle_fifo_underrun_irq(struct drm_i915_private *dev_priv);
+bool intel_fbc_can_enable(struct drm_i915_private *dev_priv);
/* intel_hdmi.c */
void intel_hdmi_init(struct drm_i915_private *dev_priv, i915_reg_t hdmi_reg,
diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
index d7d1ac7..6c9d704 100644
--- a/drivers/gpu/drm/i915/intel_fbc.c
+++ b/drivers/gpu/drm/i915/intel_fbc.c
@@ -862,7 +862,7 @@ static bool intel_fbc_can_activate(struct intel_crtc *crtc)
return true;
}
-static bool intel_fbc_can_enable(struct drm_i915_private *dev_priv)
+bool intel_fbc_can_enable(struct drm_i915_private *dev_priv)
{
struct intel_fbc *fbc = &dev_priv->fbc;
diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
index da48af1..ef04c7e 100644
--- a/drivers/gpu/drm/i915/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/intel_fbdev.c
@@ -211,7 +211,8 @@ static int intelfb_create(struct drm_fb_helper *helper,
* This also validates that any existing fb inherited from the
* BIOS is suitable for own access.
*/
- vma = intel_pin_and_fence_fb_obj(&ifbdev->fb->base, DRM_MODE_ROTATE_0);
+ vma = intel_pin_and_fence_fb_obj(&ifbdev->fb->base, DRM_MODE_ROTATE_0,
+ NULL, INVALID_PIPE);
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
goto out_unlock;
--
2.7.4
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