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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