Constant MSP Packet errors and very slow MSP data rate as a result

[b14ckyy]

Somewhere between #8495 and #8493 something changed that causes MSP throwing 2-3 packet errors per second on F411 FCs. Confirmed on F411-WING, F411-WSE
Only seems to affect F411 targets, specifically the MATEKF411SE. MATEKF405SE shows no problem.
Packet errors constantly raise and the data rate is extremely low. Applying a DIFF in CLI also aborts at one point and skips a bunch of settings suddenly.

Saw it the first time on e088782 but then narrowed it down to somewhere between the above mentioned PRs. #8495 works fine.

Tasks look weird. The percentages and rates are totally fine but the total ms are like 4-5x higher on that build:

Task list         rate/hz  max/us  avg/us maxload avgload     total/ms
 0 -       SYSTEM       9      12       1    0.5%    0.5%      4393
 1 -          PID     972     135     107   13.6%   10.9%      9231
 2 -         GYRO    3875      30      19   12.1%    7.8%      6465
 3 -           RX       9      56      50    0.5%    0.5%        46
 4 -       SERIAL      99   110671      21 1096.1%    0.7%       489
 5 -      BATTERY      49      23      20    0.6%    0.5%        85
 6 -  TEMPERATURE      99       4       2    0.5%    0.5%        13
 7 -       BEEPER      99      13       6    0.6%    0.5%        56
10 -         BARO      43     235     156    1.5%    1.1%       600
14 -    TELEMETRY     480      22       3    1.5%    0.6%       210
17 -          OSD     244    1941      18   47.8%    0.9%       402
18 -          CMS      49       4       2    0.5%    0.5%         5
21 -      VTXCTRL       4       3       1    0.5%    0.5%         0
22 -  PROGRAMMING       9      25      20    0.5%    0.5%        17
24 -          AUX      99       7       3    0.5%    0.5%        26
25 - SPORT MASTER     480       4       1    0.6%    0.5%        42
Task check function             2       1                         1
Total (excluding SERIAL)                    81.8%   26.3

I also tried commit #8493 that does not show MSP Packet errors. Task times are much lower here.

Task list         rate/hz  max/us  avg/us maxload avgload     total/ms
 0 -       SYSTEM       9      11       0    0.5%    0.5%       910
 1 -          PID     974     132     108   13.3%   11.0%      1957
 2 -         GYRO    3891      29      20   11.7%    8.2%      1298
 3 -           RX       9      57      50    0.5%    0.5%         9
 4 -       SERIAL      99   115922      32 1148.1%    0.8%       233
 5 -      BATTERY      49      27      20    0.6%    0.5%        17
 6 -  TEMPERATURE     100       4       2    0.5%    0.5%         2
 7 -       BEEPER      99      12       6    0.6%    0.5%        12
10 -         BARO      43     241     156    1.5%    1.1%       126
14 -    TELEMETRY     482      22       3    1.5%    0.6%        39
17 -          OSD     243    1937      25   47.5%    1.1%        83
18 -          CMS      49       4       2    0.5%    0.5%         1
21 -      VTXCTRL       4       1       1    0.5%    0.5%         0
22 -  PROGRAMMING       9      25      20    0.5%    0.5%         3
24 -          AUX      99      10       3    0.5%    0.5%         5
25 - SPORT MASTER     482       4       1    0.6%    0.5%         8
Task check function             2       1                         0
Total (excluding SERIAL)                    80.8%   27.0%

The issue MIGHT also cause issues in flight. I had some strange uncommanded movements of the plane I can't remember that I had this behavior before. I aborted the flight afterwards as my location was over water.

[MrD-RC]

Are you sure those PRs are right? They're 5 years old.

[b14ckyy]

@MrD-RC lol seems I accidently copied the Firmware Build Numbers and not the PR numbers.

[shota3527]

@DzikuVx
I did some investigation and found this commit 2e5c90fd5fff08081780f36a70848272452eedd is causing the issue
please have a look

[shota3527]

I have found all sensor icons is dead in 6.0.0fp2 configurator, maybe i need to use the latest master of the configurator?

[b14ckyy]

@shota3527 do you mean these? They work for me in master and FP2 as well

[DzikuVx]

@shota3527 you need latest firmware and configurator. FP2 will not work with current master of firmware

[b14ckyy]

@DzikuVx I guess you mean for the Icon issue?

But the Task time issue on F411 is unrelated. It happens also with latest configurator master, built 2 days ago.

[shota3527]

i have tried the latest master c398c52 with latest configurator master 1a33ca1b
on MATEKF411SE_SS2_CH6. i did not see packet error anymore.
So i think the packet error issue is caused by the 6.0.0fp configurator trying to fetch imu2 data

[b14ckyy]

OK I will doublecheck in the evening with a brand new build. The last build of the configurator that I used was from October 29th.

[b14ckyy]

Alright, I rebased my fork now with the latest upstream and can confirm that the issue is gone. Thank you both for looking into it! I'll close this now.