Quoting Michael Yang (2019-05-14 08:55:37) > On Thu, May 09, 2019 at 12:46:05PM +0100, Chris Wilson wrote: > > Quoting Michael Yang (2019-05-09 05:34:11) > > > If all the sync points were signaled in both fences a and b, > > > there was only one sync point in merged fence which is a_fence[0]. > > > The Fence structure in android framework might be confused about > > > timestamp if there were any sync points which were signaled after > > > a_fence[0]. It might be more reasonable to use timestamp of last signaled > > > sync point to represent the merged fence. > > > The issue can be found from EGL extension ANDROID_get_frame_timestamps. > > > Sometimes the return value of EGL_READS_DONE_TIME_ANDROID is head of > > > the return value of EGL_RENDERING_COMPLETE_TIME_ANDROID. > > > That means display/composition had been completed before rendering > > > was completed that is incorrect. > > > > > > Some discussion can be found at: > > > https://urldefense.proofpoint.com/v2/url?u=https-3A__android-2Dreview.googlesource.com_c_kernel_common_-2B_907009&d=DwIFaQ&c=bq9ppmgvSw3oQFfR871D_w&r=Ngg6vhouPkgwSIbDMU7rDN0ZfT2Qax50xuWkXXqQ3zw&m=N9R9dXGJ3zk0e0gXNM4tsiro7xCOLlWx6c3HAEseSSw&s=6sY2t9i2wvylWH-rPUlvY1MIuWKjCPzT8SeCgpZOIGk&e= > > > > > > Signed-off-by: Michael Yang <michael.yang@xxxxxxxxxx> > > > --- > > > Hi, > > > I didn't get response since I previously sent this a month ago. > > > Could someone have a chance to look at it please? > > > Thanks. > > > drivers/dma-buf/sync_file.c | 25 +++++++++++++++++++++++-- > > > 1 file changed, 23 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c > > > index 4f6305c..d46bfe1 100644 > > > --- a/drivers/dma-buf/sync_file.c > > > +++ b/drivers/dma-buf/sync_file.c > > > @@ -274,8 +274,29 @@ static struct sync_file *sync_file_merge(const char *name, struct sync_file *a, > > > for (; i_b < b_num_fences; i_b++) > > > add_fence(fences, &i, b_fences[i_b]); > > > > > > - if (i == 0) > > > - fences[i++] = dma_fence_get(a_fences[0]); > > > + /* If all the sync pts were signaled, then adding the sync_pt who > > > + * was the last signaled to the fence. > > > + */ > > > + if (i == 0) { > > > + struct dma_fence *last_signaled_sync_pt = a_fences[0]; > > > + int iter; > > > + > > > + for (iter = 1; iter < a_num_fences; iter++) { > > > > If there is more than one fence, sync_file->fence is a fence_array and > > its timestamp is what you want. If there is one fence, sync_file->fence > > is a pointer to that fence, and naturally has the right timestamp. > > > > In short, this should be handled by dma_fence_array_create() when given > > a complete set of signaled fences, it too should inherit the signaled > > status with the timestamp being taken from the last fence. It should > > also be careful to inherit the error status. > > -Chris > Thanks Chris for the inputs. For this case, there will be only one fence > in sync_file->fence after doing sync_file_merge(). Regarding to the current > implementation, dma_fence_array_create() is not called as num_fences is equal > to 1. I was wondering do you suggest that we pass a complete set of signaled > fences to sync_file_set_fence() and handle it in dma_fence_array_create(). > Thanks. No, in the case there is only one fence, we just inherit its timestamp along with its fence status. (A single fence is the degenerate case of a fence array.) -Chris
