Hi all, This is a follow up patch from this discussion [1]. It should be seen more as a starting point to introduce better handling of time per frame in v4l2. Quoting Hans Verkuil from [1]: 1) "Add a flag V4L2_DV_FL_CAN_DETECT_REDUCED_FPS. If set, then the hw can detect the difference between regular fps and 1000/1001 fps. Note: this is only valid for timings of VIC codes with the V4L2_DV_FL_CAN_REDUCE_FPS flag set." 2) "Allow V4L2_DV_FL_REDUCED_FPS to be used for receivers if V4L2_DV_FL_CAN_DETECT_REDUCED_FPS is set." 3) "For standard VIC codes the pixelclock returned by query_dv_timings is that of the corresponding VIC timing, not what is measured. This will ensure fixed fps values" 4) "g_parm should calculate the fps based on the v4l2_bt_timings struct, looking at the REDUCES_FPS flags. For those receivers that cannot detect the difference, the fps will be 24/30/60 Hz, for those that can detect the difference g_parm can check if both V4L2_DV_FL_CAN_DETECT_REDUCED_FPS and V4L2_DV_FL_REDUCED_FPS are set and reduce the fps by 1000/1001." ----------- In terms of implementation: - Point 1) is done in patch 1/3 - Point 2) and 3) should be done by a HDMI Receiver driver (I think?). - Point 4) is done in patch 2/3. - The patch 3/3 is a simple implementation (which was not tested) in the cobalt driver ----------- [1] https://patchwork.kernel.org/patch/9609441/ Best regards, Jose Miguel Abreu Cc: Carlos Palminha <palminha@xxxxxxxxxxxx> Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> Cc: Hans Verkuil <hans.verkuil@xxxxxxxxx> Cc: linux-media@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Jose Abreu (3): [media] videodev2.h: Add new DV flag CAN_DETECT_REDUCED_FPS [media] v4l2-dv-timings: Introduce v4l2_calc_timeperframe helper [media] cobalt: Use v4l2_calc_timeperframe helper drivers/media/pci/cobalt/cobalt-v4l2.c | 9 +++++-- drivers/media/v4l2-core/v4l2-dv-timings.c | 39 +++++++++++++++++++++++++++++++ include/media/v4l2-dv-timings.h | 11 +++++++++ include/uapi/linux/videodev2.h | 7 ++++++ 4 files changed, 64 insertions(+), 2 deletions(-) -- 1.9.1
