On Fri, Nov 15, 2019 at 12:52:49PM -0800, Matt Roper wrote:
On Mon, Nov 11, 2019 at 12:50:25PM -0800, Lucas De Marchi wrote:
When we call intel_dsb_get(), the dsb initialization may fail for
various reasons. We already log the error message in that path, making
it unnecessary to trigger a warning that refcount == 0 when calling
intel_dsb_put().
So here we simplify the logic and do lazy shutdown: leaving the extra
refcount alive so when we call intel_dsb_put() we end up calling
i915_vma_unpin_and_release().
Signed-off-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
Due to the lack of any actual concurrency, it seems like we could
eventually get rid of the whole get/put design and just allocate the
buffer once (and pin it during the prepare step). But this seems good
I assumed this was designed to accept the pattern
intel_dsb_get();
intel_dsb_get();
intel_dsb_put();
intel_dsb_put();
enough for now.
Reviewed-by: Matt Roper <matthew.d.roper@xxxxxxxxx>
thanks
Lucas De Marchi
---
drivers/gpu/drm/i915/display/intel_dsb.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c
index 4feebbeb0b0c..858af6be9c36 100644
--- a/drivers/gpu/drm/i915/display/intel_dsb.c
+++ b/drivers/gpu/drm/i915/display/intel_dsb.c
@@ -102,6 +102,7 @@ intel_dsb_get(struct intel_crtc *crtc)
struct intel_dsb *dsb = &crtc->dsb;
struct drm_i915_gem_object *obj;
struct i915_vma *vma;
+ u32 *buf;
intel_wakeref_t wakeref;
if (!HAS_DSB(i915))
@@ -110,7 +111,6 @@ intel_dsb_get(struct intel_crtc *crtc)
if (++dsb->refcount != 1)
return dsb;
- dsb->id = DSB1;
wakeref = intel_runtime_pm_get(&i915->runtime_pm);
obj = i915_gem_object_create_internal(i915, DSB_BUF_SIZE);
@@ -123,22 +123,29 @@ intel_dsb_get(struct intel_crtc *crtc)
if (IS_ERR(vma)) {
DRM_ERROR("Vma creation failed\n");
i915_gem_object_put(obj);
- dsb->refcount--;
goto err;
}
- dsb->cmd_buf = i915_gem_object_pin_map(vma->obj, I915_MAP_WC);
- if (IS_ERR(dsb->cmd_buf)) {
+ buf = i915_gem_object_pin_map(vma->obj, I915_MAP_WC);
+ if (IS_ERR(buf)) {
DRM_ERROR("Command buffer creation failed\n");
- i915_vma_unpin_and_release(&vma, 0);
- dsb->cmd_buf = NULL;
- dsb->refcount--;
goto err;
}
+
+ dsb->id = DSB1;
dsb->vma = vma;
+ dsb->cmd_buf = buf;
err:
+ /*
+ * Set cmd_buf to NULL so the writes pass-through, but leave the
+ * dangling refcount to be removed later by the corresponding
+ * intel_dsb_put(): the important error message will already be
+ * logged above.
+ */
+ dsb->cmd_buf = NULL;
intel_runtime_pm_put(&i915->runtime_pm, wakeref);
+
return dsb;
}
--
2.24.0
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--
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation
(916) 356-2795
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