Hi Andrey, On 2017-08-02 09:57, Andrey Smirnov wrote: > On Tue, Aug 1, 2017 at 7:38 PM, Stefan Agner <[email protected]> wrote: >> Hi, >> >> Linux 4.13-rc3 seems to freeze on a Colibri iMX7: >> > > Hi Stefan, sorry to hear about that. > >> ... >> 8021q: 802.1Q VLAN Support v1.8 >> Key type dns_resolver registered >> Registering SWP/SWPB emulation handler >> vdd1p0d: supplied by DCDC3 > > From looking briefly at the Colibir iMX7's device tree file and given > the log line above it seems that the board has slightly different > "vdd1p0d" power supply configuration, so it might be a good starting > point to investigate. >
That was a helpful hint, removing the vdd1p0d supply-in seems to fix the issue. The supply seems to cause deferred probe which seems to create the issue. >> asoc-simple-card sound: sgtl5000 <-> 308a0000.sai mapping ok >> <freeze> >> > > Not sure, but this might be a point where GPC driver will get probed > (drivers/soc/imx/gpcv2.c) and it's possible that some of the code I > wrote does not handle failure cases well. > >> I started a bisect run and I had a hard time to get properly through >> imx-dt-4.13. On the imx-dt branch the i.MX 7 GPC changes seem to cause >> the UART to only output garbage: >> > > I don't really have a good theory WRT UART, unfortunately. > >> ... >> io scheduler mq-deadline registered >> io scheduler kyber registered >> imx7-pgc imx7-pgc-domain.1: Failed to get domain's regulator >> > > The line above would be another clue in favor of differences in > "vdd1p0d" configuration somehow affecting things, because > "imx7-pgc-domain.1' is a PCIe power domain and it uses "vdd1p0d" as a > power supply. > > �������������������������������������������������~88���������������� >> >> It turned out at the merge point 2cb6115deba0 (Merge tag 'imx-dt-4.13' >> of...) the behavior changed to the freeze seen in 4.13-rc3. >> >> Reverting 0f90b43ac71b (ARM: dts: imx7s: Add node for GPC) helped in >> both cases, and when using v4.13-rc3 (I also had to revert a816d5750edf >> and 34adfaa3d404 which depend on this GPC change). >> >> I assume that the merge adds driver changes which changes the behavior >> of the GPC driver, hence freeze vs. garbage? >> >> At the moment it is unclear to me why the GPC change leads to freezes on >> our platform. On which platform have this changes been tested? > > AFAIK it was tested with imx7-sdb as well as imx7d-cl-som. Ok, since both do not use a supply-in that makes sense. Further debugging unveiled that imx7_pgc_domain_probe executes pm_genpd_init twice when the regulator requests deferred probing. The easiest fix seems to reorder pm_genpd_init vs. devm_regulator_get_optional. With that I can keep boot with supply-in specified. I will send out a patch soon. Thanks! -- Stefan
