On Tue, 26 Oct 2021 at 06:00, Saravana Kannan <saravanak@xxxxxxxxxx> wrote: > > On Fri, Oct 22, 2021 at 10:00 AM Amit Pundir <amit.pundir@xxxxxxxxxx> wrote: > > > > On Fri, 22 Oct 2021 at 05:13, Saravana Kannan <saravanak@xxxxxxxxxx> wrote: > > > > > > On Thu, Oct 21, 2021 at 4:21 AM Amit Pundir <amit.pundir@xxxxxxxxxx> wrote: > > > > > > > > Hi Saravana, > > > > > > > > This patch broke v5.15-rc6 on RB5 (sm8250 | qcom/qrb5165-rb5.dts). > > > > I can't boot past this point https://www.irccloud.com/pastebin/raw/Nv6ZwHmW. > > > > > > Amit top posting? How did that happen? :) > > > > > > The fact you are seeing this issue is super strange though. The driver > > > literally does nothing other than allowing some sync_state() callbacks > > > to happen. I also grepped for the occurence of "simple-bus" in > > > arch/arm64/boot/dts/qcom/ and the only instance for 8250 is for the > > > soc node. > > > > > > The only thing I can think of is that without my patch some > > > sync_state() callbacks weren't getting called and maybe it was masking > > > some other issue. > > > > > > Can you try to boot with this log (see log patch below) and see if the > > > device hangs right after a sync_state() callback? Also, looking at the > > > different sync_state() implementations in upstream, I'm guessing one > > > of the devices isn't voting for interconnect bandwidth when it should > > > have. > > > > > > Another thing you could do is boot without the simple-bus changes and > > > then look for all instances of "state_synced" in /sys/devices and then > > > see if any of them has the value "0" after boot up is complete. > > > > Turned out RB5 is not even reaching up to > > device_links_flush_sync_list() and seem to be stuck somewhere in > > device_links_driver_bound(). So I added more print logs to narrow down > > to any specific lock state but those additional prints seem to have > > added enough delay to unblock that particular driver (Serial: > > 8250/16550 driver if I understood the logs correctly) and I eventually > > booted to UI. > > Ugh... I think I know what's going on. It popped into my head over the weekend. > > Couple of ways to confirm my theory: > 1. After it finishes booting in both cases, can you compare the output > of the command below? I'm expecting to see a significant drop in the > number of device links. > ls -l /sys/class/devlink | wc -l > On a successful boot with debug prints: rb5:/ $ ls -l /sys/class/devlink | wc -l 245 Booting with this SIMPLE_PM_BUS patch reverted: rb5:/ $ ls -l /sys/class/devlink | wc -l 248 > 2. Can you try out this terrible hack patch (not final fix, no code > reviews please) on top of Tot to see if it fixes your issue without > having to add hacky logs? > No luck booting with the following hack patch either. Regards, Amit Pundir > Thanks, > Saravana > > --- a/drivers/bus/simple-pm-bus.c > +++ b/drivers/bus/simple-pm-bus.c > @@ -38,10 +38,12 @@ static int simple_pm_bus_probe(struct platform_device *pdev) > * a device that has a more specific driver. > */ > if (match && match->data) { > - if (of_property_match_string(np, "compatible", > match->compatible) == 0) > + if (of_property_match_string(np, "compatible", > match->compatible) == 0) { > + of_platform_populate(np, NULL, lookup, &pdev->dev); > return 0; > - else > + } else { > return -ENODEV; > + } > }
