On Mon, 20 Apr 2020 23:11:18 +0200 "H. Nikolaus Schaller" <hns@xxxxxxxxxxxxx> wrote: > 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. > So I guess without idling uarts? > 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. > Hmm, last summer I had problems even without that patch reading temperature while doing umts transfers. Maybe there are some connections, maybe not. For that scenario we might have emc issues, thermal problems or a real kernel problem. Regards, Andreas
