On Wed, Jul 27, 2016 at 10:31:52AM -0600, Jason Gunthorpe wrote: > On Wed, Jul 27, 2016 at 11:05:14AM -0500, George Wilson wrote: > > > > Yes, generally Linux expects DT to be set correctly by the boot > > > firmware. Early firmware needs to know the TPM type anyhow to do the > > > TPM setup, so this doesn't seem like a realistic scenario. > > > > A reset is required after upgrade/downgrade. But the version still > > needs to be detected by the firmware somehow. It could be configured > > manually in firmware state after the upgrade/downgrade to properly set > > the property, which seems much less desirable than a probe. > > Well, the firmware has to take care of this. If the firmware wants to > support switchable firmware it needs to be able to do probe that works > with all the firmware versions. > > ACPI and DT both expect the TPM version to be passed to the OS, it is > up to the firmware to do that correctly.. > > The fact you've already seen TPM2 probing failures makes me very > reluctant to turn it on more broadly, and maybe even think we should > get rid of it from tis too..
Cool, that clarifies it precisely: the expectation is that firmware will do any necessary probing and pass the property up in the device tree. All drivers supporting OF must use the data property as a flag for 2.0 for models capable of 2.0 function. > > Jason > -- George Wilson IBM Linux Technology Center Security Development ------------------------------------------------------------------------------ _______________________________________________ tpmdd-devel mailing list tpmdd-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/tpmdd-devel
