Messages in this thread |  | | Date | Fri, 27 Mar 2020 23:48:31 +0530 | From | Sai Prakash Ranjan <> | Subject | Re: [PATCH] iommu/arm-smmu: Demote error messages to debug in shutdown callback |
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Hi Rob,
On 2020-03-27 21:47, Rob Clark wrote: > On Fri, Mar 27, 2020 at 8:10 AM Sai Prakash Ranjan > <saiprakash.ranjan@codeaurora.org> wrote: >> >> Hi Robin, >> >> Thanks for taking a look at this. >> >> On 2020-03-27 19:42, Robin Murphy wrote: >> > On 2020-03-27 1:28 pm, Sai Prakash Ranjan wrote: >> >> Currently on reboot/shutdown, the following messages are >> >> displayed on the console as error messages before the >> >> system reboots/shutdown. >> >> >> >> On SC7180: >> >> >> >> arm-smmu 15000000.iommu: removing device with active domains! >> >> arm-smmu 5040000.iommu: removing device with active domains! >> >> >> >> Demote the log level to debug since it does not offer much >> >> help in identifying/fixing any issue as the system is anyways >> >> going down and reduce spamming the kernel log. >> > >> > I've gone back and forth on this pretty much ever since we added the >> > shutdown hook - on the other hand, if any devices *are* still running >> > in those domains at this point, then once we turn off the SMMU and let >> > those IOVAs go out on the bus as physical addresses, all manner of >> > weirdness may ensue. Thus there is an argument for *some* indication >> > that this may happen, although IMO it could be downgraded to at least >> > dev_warn(). >> > >> >> Any pointers to the weirdness here after SMMU is turned off? >> Because if we look at the call sites, device_shutdown is called >> from kernel_restart_prepare or kernel_shutdown_prepare which would >> mean system is going down anyways, so do we really care about these >> error messages or warnings from SMMU? >> >> arm_smmu_device_shutdown >> platform_drv_shutdown >> device_shutdown >> kernel_restart_prepare >> kernel_restart >> > > I'd guess that drm/msm is not detaching all of it's UNMANAGED domains > in shutdown. Although *presumably* the device_link stuff would > prevent the SMMU from shutting down while gpu/display is still active? > If not I think we have bigger problems. >
Where is the shutdown callback in drm/msm? I don't see any...
Thanks, Sai
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