Hi Enric and Mark, On 6/29/20 8:05 PM, Enric Balletbo i Serra wrote: > Hi Chanwoo and Marc, > > On 29/6/20 13:09, Chanwoo Choi wrote: >> Hi Enric, >> >> Could you check this issue? Your patch[1] causes this issue. >> As Marc mentioned, although rk3399-dmc.c handled 'rockchip,pmu' >> as the mandatory property, your patch[1] didn't add the 'rockchip,pmu' >> property to the documentation. >> > > I think the problem is that the DT binding patch, for some reason, was missed > and didn't land. The patch seems to have all the required reviews and acks. > > https://patchwork.kernel.org/patch/10901593/ > > Sorry because I didn't notice this issue when 9173c5ceb035 landed. And thanks > for fixing the issue. If the 'rockchip,pmu' propery is mandatory, instead of Mark's patch, we better to require the merge of patch[1] to DT maintainer. [1] https://patchwork.kernel.org/patch/10901593/ > > Best regards, > Enric > >> [1] 9173c5ceb035 ("PM / devfreq: rk3399_dmc: Pass ODT >> and auto power down parameters to TF-A.") >> >> >> On 6/29/20 5:18 PM, Marc Zyngier wrote: >>> Hi Chanwoo, >>> >>> On Mon, 29 Jun 2020 03:43:37 +0100, >>> Chanwoo Choi <cw00.choi@xxxxxxxxxxx> wrote: >>>> >>>> Hi Marc, >>>> >>>> On 6/23/20 12:28 AM, Marc Zyngier wrote: >>> >>> [...] >>> >>>> It looks good to me. But, I think that it is not necessary >>>> fully kernel panic log about NULL pointer. It is enoughspsp >>>> just mentioning the NULL pointer issue without full kernel panic log. >>> >>> I personally find the backtrace useful as it allows people with the >>> same issue to trawl the kernel log and find whether it has already be >>> fixed upstream. But it's only me, and I'm not attached to it. >>> >>>> So, how about editing the patch description as following or others simply? >>>> and we need to add 'stable@xxxxxxxxxxxxxxx' to Cc list for applying it >>>> to stable branch. >>> >>> Looks good to me. >>> >>>> >>>> >>>> PM / devfreq: rk3399_dmc: Fix kernel oops when rockchip,pmu is absent >>>> >>>> Booting a recent kernel on a rk3399-based system (nanopc-t4), >>>> equipped with a recent u-boot and ATF results in the kernel panic >>>> about NULL pointer issue. >>> >>> nit: "results in a kernel panic on dereferencing a NULL pointer". >>> >>>> >>>> This turns out to be due to the rk3399-dmc driver looking for >>>> an *undocumented* property (rockchip,pmu), and happily using >>>> a NULL pointer when the property isn't there. >>>> >>>> Instead, make most of what was brought in with 9173c5ceb035 >>>> ("PM / devfreq: rk3399_dmc: Pass ODT and auto power down parameters >>>> to TF-A.") conditioned on finding this property in the device-tree, >>>> preventing the driver from exploding. >>>> >>>> Fixes: 9173c5ceb035 ("PM / devfreq: rk3399_dmc: Pass ODT and auto power down parameters to TF-A.") >>>> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx> >>>> Signed-off-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx> >>> >>> >>> Note that the biggest issue is still there: the driver is using an >>> undocumented property, and this patch is just papering over it. >>> Since I expect this property to be useful for something, it would be >>> good for whoever knows what it does to document it. >> >> Hi Marc, >> >> You are right. We have to do two step: >> 1. Add missing explanation of 'rockchip,pmu' property to dt-binding document >> 2. If possible, add 'rockchip,pmu' property node to rk3399_dmc dt node. >> >> When I tried to find usage example of 'rockchip,pmu' property, >> I found them as following: The 'rockchip,pmu' property[2] indicates >> 'PMU (Power Management Unit)'. >> >> $ grep -rn "rockchip,pmu" arch/arm64/boot/dts/ >> arch/arm64/boot/dts/rockchip/px30.dtsi:1211: rockchip,pmu = <&pmugrf>; >> arch/arm64/boot/dts/rockchip/rk3399.dtsi:1909: rockchip,pmu = <&pmugrf>; >> arch/arm64/boot/dts/rockchip/rk3368.dtsi:807: rockchip,pmu = <&pmugrf>; >> >> [2] the description of 'rockchip,pmu' property >> - https://protect2.fireeye.com/url?k=e55f0ba3-b8384f85-e55e80ec-0cc47a31384a-d9c5f6b28aba9be6&q=1&u=https%3A%2F%2Felixir.bootlin.com%2Flinux%2Fv5.7.2%2Fsource%2FDocumentation%2Fdevicetree%2Fbindings%2Fpinctrl%2Frockchip%2Cpinctrl.txt%23L40 >> >> >> If don't receive the any reply, I'll add as following: >> >> cwchoi00@chan-linux-pc:~/kernel/git.kernel/linux.chanwoo$ d >> diff --git a/Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt b/Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt >> index 0ec68141f85a..161e60ea874b 100644 >> --- a/Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt >> +++ b/Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt >> @@ -18,6 +18,8 @@ Optional properties: >> format depends on the interrupt controller. >> It should be a DCF interrupt. When DDR DVFS finishes >> a DCF interrupt is triggered. >> +- rockchip,pmu: Phandle to the syscon managing the "pmu general >> + register files". >> >> Following properties relate to DDR timing: >> >> >> > > -- Best Regards, Chanwoo Choi Samsung Electronics
