Re: [PATCH i-g-t v2 07/12] lib/igt_kms: Add support for the OUT_FENCE_PTR property

Brian Starkey
2016-12-14T16:14:00Z

Hi,

On Wed, Dec 14, 2016 at 04:05:04AM -0500, Robert Foss wrote:
>From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
>
>Add support for the OUT_FENCE_PTR property to enable setting out fences for
>atomic commits.
>
>Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
>Signed-off-by: Robert Foss <robert.foss@collabora.com>
>---
> lib/igt_kms.c | 21 ++++++++++++++++++++-
> lib/igt_kms.h | 3 +++
> 2 files changed, 23 insertions(+), 1 deletion(-)
>
>diff --git a/lib/igt_kms.c b/lib/igt_kms.c
>index 8ca49d86..fe1b356d 100644
>--- a/lib/igt_kms.c
>+++ b/lib/igt_kms.c
>@@ -175,7 +175,8 @@ const char *igt_crtc_prop_names[IGT_NUM_CRTC_PROPS] = {
> "DEGAMMA_LUT",
> "GAMMA_LUT",
> "MODE_ID",
>- "ACTIVE"
>+ "ACTIVE",
>+ "OUT_FENCE_PTR"
> };
>
> const char *igt_connector_prop_names[IGT_NUM_CONNECTOR_PROPS] = {
>@@ -2103,6 +2104,10 @@ static void igt_atomic_prepare_crtc_commit(igt_pipe_t *pipe_obj, drmModeAtomicRe
> igt_atomic_populate_crtc_req(req, pipe_obj, IGT_CRTC_ACTIVE, !!output);
> }
>
>+ if (pipe_obj->out_fence_ptr)
>+ igt_atomic_populate_crtc_req(req, pipe_obj, IGT_CRTC_OUT_FENCE_PTR,
>+ (uint64_t)(uintptr_t) pipe_obj->out_fence_ptr);
>+
> /*
> * TODO: Add all crtc level properties here
> */
>@@ -2683,6 +2688,20 @@ igt_pipe_set_gamma_lut(igt_pipe_t *pipe, void *ptr, size_t length)
> }
>
> /**
>+ * igt_pipe_set_out_fence_ptr:
>+ * @pipe: pipe pointer to which background color to be set
>+ * @fence_ptr: out fence pointer
>+ *
>+ * Sets the out fence pointer that will be passed to the kernel in
>+ * the atomic ioctl. When the kernel returns the out fence pointer
>+ * will contain the fd number of the out fence created by KMS.
>+ */
>+void igt_pipe_set_out_fence_ptr(igt_pipe_t *pipe, int64_t *fence_ptr)
>+{
>+ pipe->out_fence_ptr = fence_ptr;
>+}
>+
>+/**
> * igt_crtc_set_background:
> * @pipe: pipe pointer to which background color to be set
> * @background: background color value in BGR 16bpc
>diff --git a/lib/igt_kms.h b/lib/igt_kms.h
>index 9766807c..8eb611c0 100644
>--- a/lib/igt_kms.h
>+++ b/lib/igt_kms.h
>@@ -110,6 +110,7 @@ enum igt_atomic_crtc_properties {
> IGT_CRTC_GAMMA_LUT,
> IGT_CRTC_MODE_ID,
> IGT_CRTC_ACTIVE,
>+ IGT_CRTC_OUT_FENCE_PTR,
> IGT_NUM_CRTC_PROPS
> };
>
>@@ -316,6 +317,7 @@ struct igt_pipe {
>
> uint64_t mode_blob;
> bool mode_changed;
>+ int64_t *out_fence_ptr;

I prefer the interface that got suggested before - igt_pipe gets an
"int64_t out_fence;" member which tests can query to get the fence
value:

int igt_pipe_get_last_out_fence(igt_pipe_t *pipe);

..and the kernel only ever receives a pointer to pipe->out_fence.

The only reason I can see for a test to want to provide its own fence
pointer is to test invalid pointer values - and I think it's OK for
that test to set the property directly instead of making setting a
custom fence pointer the common case for all users.

If we don't want to get a fence for every commit then I guess there
could be a way for a test to request an out-fence for just the next
commit on a pipe (or the inverse - disable fencing for a particular
commit):

void igt_pipe_request_out_fence(igt_pipe_t *pipe);

-Brian

> };
>
> typedef struct {
>@@ -369,6 +371,7 @@ static inline bool igt_plane_supports_rotation(igt_plane_t *plane)
> void igt_pipe_set_degamma_lut(igt_pipe_t *pipe, void *ptr, size_t length);
> void igt_pipe_set_ctm_matrix(igt_pipe_t *pipe, void *ptr, size_t length);
> void igt_pipe_set_gamma_lut(igt_pipe_t *pipe, void *ptr, size_t length);
>+void igt_pipe_set_out_fence_ptr(igt_pipe_t *pipe, int64_t *fence_ptr);
>
> void igt_plane_set_fb(igt_plane_t *plane, struct igt_fb *fb);
> void igt_plane_set_fence_fd(igt_plane_t *plane, uint32_t fence_fd);
>--
>2.11.0
>