mx6DL, 4,ECSPI with linux 4.1.15,wrong delay time

[weidajang]

The chip model I use is imx6dl and the system is Linux 4.1.15. My project uses four ecspi functions,
I found a very strange phenomenon. Every time I run an existing program in the way of. / xxx, the delay operation of the program is very normal, as follows:
As you can see, my whole program finished in just a few milliseconds.

Jan 20 19:00:09 imx6qsabresd baozi[676]: [spidev1.0] serialThread.c:558 STEP -----------------------------------------------------------------
Jan 20 19:00:09 imx6qsabresd baozi[676]: [spidev1.0] serialThread.c:559 STEP :probe->key == 3
Jan 20 19:00:09 imx6qsabresd baozi[676]: [spidev1.0] serialThread.c:560 STEP second: 1611169209
Jan 20 19:00:09 imx6qsabresd baozi[676]: [spidev1.0] serialThread.c:561 STEP millisecond: 556473228
Jan 20 19:00:09 imx6qsabresd baozi[676]: [spidev1.0] serialThread.c:562 STEP -----------------------------------------------------------------
Jan 20 19:00:09 imx6qsabresd baozi[676]: [spidev1.0] serialThread.c:602 STEP -----------------------------------------------------------------
Jan 20 19:00:09 imx6qsabresd baozi[676]: [spidev1.0] serialThread.c:603 STEP 4
Jan 20 19:00:09 imx6qsabresd baozi[676]: [spidev1.0] serialThread.c:604 STEP second: 1611169209
Jan 20 19:00:09 imx6qsabresd baozi[676]: [spidev1.0] serialThread.c:605 STEP millisecond: 556473228
Jan 20 19:00:09 imx6qsabresd baozi[676]: [spidev1.0] serialThread.c:606 STEP ----------------------------------------------------------------
Jan 20 19:00:09 imx6qsabresd baozi[676]: [spidev1.0] serialThread.c:615 STEP -----------------------------------------------------------------
Jan 20 19:00:09 imx6qsabresd baozi[676]: [spidev1.0] serialThread.c:616 STEP 5
Jan 20 19:00:09 imx6qsabresd baozi[676]: [spidev1.0] serialThread.c:617 STEP second: 1611169209
Jan 20 19:00:09 imx6qsabresd baozi[676]: [spidev1.0] serialThread.c:618 STEP millisecond: 556473229
Jan 20 19:00:09 imx6qsabresd baozi[676]: [spidev1.0] serialThread.c:619 STEP -----------------------------------------------------------------

When I set the program to the daemon mode and add it to the startup script to run, it starts to run abnormally at this time.
This is shown below. It is possible that dozens of MS operations are stretched to a few seconds

Jan 20 20:25:34 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:511 VTEP --------------------Current loop : 1----------------------------
Jan 20 20:25:34 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:512 VTEP 1 :start
Jan 20 20:25:34 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:513 VTEP second: 1611174334
Jan 20 20:25:34 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:514 VTEP millisecond: 561598566
Jan 20 20:25:34 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:515 VTEP -----------------------------------------------------------------
Jan 20 20:25:34 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:532 VTEP -----------------------------------------------------------------
Jan 20 20:25:34 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:533 VTEP 2 :fill_task_mark(&cachelist) before
Jan 20 20:25:34 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:534 VTEP second: 1611174334
Jan 20 20:25:34 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:535 VTEP millisecond: 561598924
Jan 20 20:25:34 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:536 VTEP -----------------------------------------------------------------
Jan 20 20:25:41 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:543 VTEP -----------------------------------------------------------------
Jan 20 20:25:41 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:544 VTEP 3 :fill_task_mark(&cachelist) after
Jan 20 20:25:41 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:545 VTEP second: 1611174341
Jan 20 20:25:41 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:546 VTEP millisecond: 561605401
Jan 20 20:25:41 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:547 VTEP -----------------------------------------------------------------
Jan 20 20:25:42 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:589 VTEP -----------------------------------------------------------------
Jan 20 20:25:42 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:590 VTEP 4
Jan 20 20:25:42 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:591 VTEP second: 1611174342
Jan 20 20:25:42 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:592 VTEP millisecond: 561606099
Jan 20 20:25:42 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:593 VTEP -----------------------------------------------------------------
Jan 20 20:25:42 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:602 VTEP -----------------------------------------------------------------
Jan 20 20:25:42 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:603 VTEP 5
Jan 20 20:25:42 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:604 VTEP second: 1611174342
Jan 20 20:25:42 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:605 VTEP millisecond: 561606434
Jan 20 20:25:42 imx6qsabresd baozi[669]: [spidev0.0] serialThread.c:606 VTEP -----------------------------------------------------------------

This makes me very confused why. / mode is normal operation, background mode will delay more severe.

[igorpadykov]

Hi weidajang

L4.1.15 is very old kernel and not more supported, may be suggested to try latest

kernels described on

https://www.nxp.com/design/software/embedded-software/i-mx-software/embedded-linux-for-i-mx-applicat...

Best regards
igor