On 9/7/2019 4:37 PM, Animesh Manna wrote:
The lifetime of command buffer can be controlled by the dsb user
throuh refcount. Added refcount mechanism is dsb get/put call
which create/destroy dsb context.
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
Cc: Shashank Sharma <shashank.sharma@xxxxxxxxx>
Signed-off-by: Animesh Manna <animesh.manna@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_dsb.c | 22 ++++++++++++++++------
drivers/gpu/drm/i915/display/intel_dsb.h | 1 +
2 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c
index 853685751540..b951a6b5264a 100644
--- a/drivers/gpu/drm/i915/display/intel_dsb.c
+++ b/drivers/gpu/drm/i915/display/intel_dsb.c
@@ -78,7 +78,12 @@ intel_dsb_get(struct intel_crtc *crtc)
struct intel_dsb *dsb = &crtc->dsb;
intel_wakeref_t wakeref;
- if ((!HAS_DSB(i915)) || dsb->cmd_buf)
+ if (!HAS_DSB(i915))
+ return dsb;
+
+ atomic_inc(&dsb->refcount);
+
As discussed we are not solving any problem with reference counting,
rather, we are adding a complexity here. It may be useful, when we are
extending single instance of DSB to DSB pool but not right now.
I would say we drop this patch all together, and just have the simple
implementation now.
- Shashank
+ if (dsb->cmd_buf)
return dsb;
dsb->id = DSB1;
@@ -94,6 +99,7 @@ intel_dsb_get(struct intel_crtc *crtc)
if (IS_ERR(vma)) {
DRM_ERROR("Vma creation failed.\n");
i915_gem_object_put(obj);
+ atomic_dec(&dsb->refcount);
goto err;
}
@@ -102,6 +108,7 @@ intel_dsb_get(struct intel_crtc *crtc)
DRM_ERROR("Command buffer creation failed.\n");
i915_vma_unpin_and_release(&vma, 0);
dsb->cmd_buf = NULL;
+ atomic_dec(&dsb->refcount);
goto err;
}
dsb->vma = vma;
@@ -121,11 +128,14 @@ void intel_dsb_put(struct intel_dsb *dsb)
return;
if (dsb->cmd_buf) {
- mutex_lock(&i915->drm.struct_mutex);
- i915_gem_object_unpin_map(dsb->vma->obj);
- i915_vma_unpin_and_release(&dsb->vma, 0);
- dsb->cmd_buf = NULL;
- mutex_unlock(&i915->drm.struct_mutex);
+ atomic_dec(&dsb->refcount);
+ if (!atomic_read(&dsb->refcount)) {
+ mutex_lock(&i915->drm.struct_mutex);
+ i915_gem_object_unpin_map(dsb->vma->obj);
+ i915_vma_unpin_and_release(&dsb->vma, 0);
+ dsb->cmd_buf = NULL;
+ mutex_unlock(&i915->drm.struct_mutex);
+ }
}
}
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.h b/drivers/gpu/drm/i915/display/intel_dsb.h
index 7389c8c5b665..dca4e632dd3c 100644
--- a/drivers/gpu/drm/i915/display/intel_dsb.h
+++ b/drivers/gpu/drm/i915/display/intel_dsb.h
@@ -20,6 +20,7 @@ enum dsb_id {
};
struct intel_dsb {
+ atomic_t refcount;
enum dsb_id id;
u32 *cmd_buf;
struct i915_vma *vma;
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