Hi Tony, > Am 20.04.2020 um 17:08 schrieb Tony Lindgren <tony@xxxxxxxxxxx>: > > * H. Nikolaus Schaller <hns@xxxxxxxxxxxxx> [200417 21:04]: >> To me it looks as if reading hqd too quickly after omap_hdq_runtime_resume() >> may be part of the problem, although it is 0.4 seconds between [ 18.355163] >> and [ 18.745269]. So I am not sure about my interpretation. >> >> A different attempt for interpretation may be that trying to read the >> slave triggers omap_hdq_runtime_resume() just before doing the >> first hdq_read_byte(). > > Hmm so I wonder if adding msleep(100) at the end of > omap_hdq_runtime_resume() might help? I have tried and initially it did boot and work once. But after the second boot/reboot the effect was back. This is something I have observed previously, that the issue is there in ca. 9 or 10 boot attempts. So I would assume some race condition with udev reading the uevent file of the bq27xxx bus client and hence through hdq. I already had noticed some hqd_read activity right after probing success. I had also tried to change pm_runtime_set_autosuspend_delay(, 1000) with no success. And I tried to call omap_hdq_runtime_resume() at the end of probe. The only maybe important observation was when I disabled all kernel modules except *hdq*.ko and *bq27*.ko. Then I did only get an emergency shell so that it is quite similar to the scenario Andreas has tested. With this setup it did work. I then tried to reenable other kernel modules but the result wasn't convincing that it gives a reliable result. So I have still no clear indication when the problem occurs and when not. BR and thanks, Nikolaus
