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

Robert Foss
2016-12-16T08:21:49Z

On 2016-12-14 11:13 AM, Brian Starkey wrote:
> 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

Now I see what you meant in the v1 discussion, I'll amend the
implementation in v3 to be the one mentioned above.

The only question I have is about igt_pipe_get_last_out_fence(), is it
really necessary? I don't foresee a function like that ever doing more
than just returning a struct member. Is it not a bit redundant?

Rob.

>
>> };
>>
>> 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
>>