Hi Sakari,
Em Mon, 8 May 2017 18:03:12 +0300 Sakari Ailus sakari.ailus@linux.intel.com escreveu:
Hello,
This is a rebased and partially reworked version of the vb2 cache hints support patch series posted by first myself, then Laurent and then myself again.
I'm still posting this as RFC primarily because more testing and driver changes will be needed. In particular, a lot of platform drivers assume non-coherent memory but are not properly labelled as such.
The main issue I see is that, if the driver doesn't "annotate" if it is requiring coherent or non-coherent memory, VB2 should be preserving its old behavior, as, otherwise, it will risk causing regressions.
So, perhaps instead of creating a single flag V4L2_BUF_FLAG_NO_CACHE_SYNC, it would make sense to create two flags, using either one of them on newer drivers. For old drivers that won't set either, it would keep the current behavior.
Thanks, Mauro