Messages in this thread |  | | Date | Fri, 27 Mar 2020 20:39:46 +0530 | From | Sai Prakash Ranjan <> | Subject | Re: [PATCH] iommu/arm-smmu: Demote error messages to debug in shutdown callback |
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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
Thanks, Sai
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