question: interconnect: changes in 5.10 / imx8mq ?

[Martin Kepplinger]

hi,

what I've used on v5.9 on imx8mq in order to hook up dram frequency to 
interconnect (via mxsfb/lcdif) - and has worked fine - is:

* add the NOC node description with "#interconnect-cells = <1>;"
https://source.puri.sm/martin.kepplinger/linux-next/-/commit/8a6b8486a3e94e2886bde01000f9532e03d243a4
(original author is Leonard. I'll preserve authorship when submitting)

* add "interconnects = <&noc IMX8MQ_ICM_LCDIF &noc IMX8MQ_ICS_DRAM>;
" to lcdif:
https://source.puri.sm/martin.kepplinger/linux-next/-/commit/6c4bbcdc315da01a9dc8bbda36290587ce1ed33a

* hook up the driver
https://source.puri.sm/martin.kepplinger/linux-next/-/commit/63679bcfa586578fc4345010a30ff7ac1af4c3c6
(I know this doesn't use devm_* and has to be cleaned up)


on v5.9 this would nicely have the driver's value set:

  node                                  tag          avg         peak
--------------------------------------------------------------------
NOC                                                   0       678900
   30320000.lcd-controller                0            0       678900
DRAM                                                  0       678900
   30320000.lcd-controller                0            0       678900
(...)

now on 5.10, I get dram always running at the highest speed because the 
*node* "requests" a lot, see the interconnect_summary:

  node                                  tag          avg         peak
--------------------------------------------------------------------
NOC                                          2147483647   2147483647
   30320000.lcd-controller                0            0       678900
DRAM                                         2147483647   2147483647
   30320000.lcd-controller                0            0       678900
(...)

the above is with screen on of course, as can be seen by the value from 
the driver. That *is* set to 0 as expected, but still, the "2147483647" 
remains:

  node                                  tag          avg         peak
--------------------------------------------------------------------
NOC                                          2147483647   2147483647
   30320000.lcd-controller                0            0            0
DRAM                                         2147483647   2147483647
   30320000.lcd-controller                0            0            0
(...)



what am I doing wrong on recent kernels?

thanks a lot!

                                   martin