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Status: Untriaged
Owner: ----
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EstimatedDays: ----
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OS: Chrome
Pri: 2
Type: Bug



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Fix tpm_tis parameters in kernel command line for cr50

Project Member Reported by apronin@chromium.org, Mar 6 2018

Issue description

[Spawned from issue 786528 as a more generic case, applicable to pre 4.14 kernels as well.]

Since https://crrev.com/3969001 we have tpm_tis.force=1 and tpm_tis.interrupts=0 in kernel commandline. For systems with cr50 that leads to an unnecessary probe for tpm_tis driver. In syslog we see something similar to
  tpm tpm0: tpm_transmit: tpm_send: error -5
  tpm_tis: probe of tpm_tis failed with error -5
before cr50 probe runs.

1) It is confusing to the people who check the syslogs while debugging various issues. Almost every report that comes for possibly tpm-related problems from non-tpm-focused engineers point out this probe failure in the logs as a potential root cause. 

2) It may cause issues, in case the default memory region overlaps with some actual device registers.

These parameters should be removed at least for systems with cr50.

But do we still need them for devices with 1.2 as well? The original justification says that it is needed "before we fix the PNP table in the firmware". Is it fixed by now on all non-EOLed devices?
 
Kind of similar to crbug.com/786528.
Components: OS>Kernel>TPM
Labels: Cros-Hwsec-Ready

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