i.MX 8 measuring UI update duration

[igorvurdelja]

Hello everyone,

I am using Linux kernel imx_4.19.35_1.0.0 on i.MX 8.

I want to measure the time between touch event and UI response.

For now I managed to obtain timestamp when touch event happens, but I am still missing the timestamp when UI updated.

My idea was to catch the timestamp when galcore communicates with HW, but the issue is that Vivante driver is closed source and I do not know where to place kprobe.

Does anyone have idea how can I catch the moment when DRM buffers are updated or the moment when galcore communicates with HW?

Thanks in advance,

Igor

[Bio_TICFSL]

Hello igorvurdeljia,

The bsp don´t have this feature you should be added, I think to the touch calibrator you can add a timestamp but no en GPU. You should follow the steps to operate touch calibrator:

# weston-touch-calibrator /* List all touch devices */

For example, probably like this: /* Yours may be different from below, but simliar */
could not load cursor 'dnd-move'
could not load cursor 'dnd-copy'
could not load cursor 'dnd-none'
device "/sys/devices/platform/5a800000.i2c/i2c-16/16-002c/input/input1/event1" - head "DPI-1"
# weston-touch-calibrator /sys/devices/platform/5a800000.i2c/i2c-16/16-002c/input/input1/event1

/* calibrate touch screen */

You can add some DEBUG messages into "save_touch_device_calibration()" function to check if data has been save.

Have a nice day!