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It appears that IRQ Hold / cfgIrqHold is a 16 bit value.  With it set to 65535, 'BUG: soft lockup' messages are still seen at more or less the same rate as with the default value.  The setting has no obvious effect on deadtime at 1 MHz trigger rate.

dmesg gives the IRQ number being used for a datadev device:

[Thu Feb 10 17:35:36 2022] datadev 0000:41:00.0: Init: IRQ 369

dstat can show the IRQ rate (interrupts/sec), here for an idle system:

claus@drp-srcf-cmp005:~$ dstat -tiy -I 369,370 10
----system---- -interrupts ---system--
     time     | 369   370 | int   csw
10-02 13:23:45| 101   101 |3699  5985
10-02 13:23:55| 100   100 |3807  6088

HSD

• look at configured parameters using (for example) "hsdpva DAQ:LAB2:HSD:DEV06_3D:A"
• for kcu firmware that is built to use both QSFP links, the naming of the qsfp's is swapped.  i.e. the qsfp that is normally called /dev/datadev_0 is now called /dev/datadev_1
• HSD is not configured to do anything (Check the HSD config tab for no channels enabled)
• if hsd timing frames are not being received at 929kHz (status here), click TxLink Reset in XPM window.  Typically when this is an issue the receiving rate is ~20kHz.
• The HSD readoutGroup number does not match platform number in .cnf file (Check the HSD "Config" tab)
• also check that HEADERCNTL0 is incrementing in "Timing" tab of HSD cfg window.
• in hsd Timing tab timpausecnt is number of clocks we are dead
• in hsd expert window "full threshold(events)" sets threshold for hsd deadtime
• in hsd Buffer tab "fex free events" and "raw free events" are the current free events.
• in hsd status window "write fifo count" is number of timing headers waiting for HSD data to associate.
• "readcntsum" on hsd timing tab goes up when we send a transition OR L1Accepts. "trigcntsum" counts L1Accepts only.
• check kcuStatus for "locPause" non-zero (a low level pgp FIFO being full).  If this happens then:  configure hsd, clear readout, reboot drp node with KCU

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