[PATCH 5.4 11/78] tpm: Revert "tpm_tis_core: Turn on the TPM before probing IRQs"

Greg Kroah-Hartman
2020-01-14T10:03:12Z

From: Stefan Berger <stefanb@linux.ibm.com>

commit aa4a63dd981682b1742baa01237036e48bc11923 upstream.

There has been a bunch of reports (one from kernel bugzilla linked)
reporting that when this commit is applied it causes on some machines
boot freezes.

Unfortunately hardware where this commit causes a failure is not widely
available (only one I'm aware is Lenovo T490), which means we cannot
predict yet how long it will take to properly fix tpm_tis interrupt
probing.

Thus, the least worst short term action is to revert the code to the
state before this commit. In long term we need fix the tpm_tis probing
code to work on machines that Stefan's fix was supposed to fix.

Fixes: 21df4a8b6018 ("tpm_tis: reserve chip for duration of tpm_tis_core_init")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=205935
Cc: stable@vger.kernel.org
Cc: Jerry Snitselaar <jsnitsel@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Xiaoping Zhou <xiaoping.zhou@intel.com>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/char/tpm/tpm_tis_core.c | 2 --
1 file changed, 2 deletions(-)

--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -980,7 +980,6 @@ int tpm_tis_core_init(struct device *dev
goto out_err;
}

- tpm_chip_start(chip);
if (irq) {
tpm_tis_probe_irq_single(chip, intmask, IRQF_SHARED,
irq);
@@ -990,7 +989,6 @@ int tpm_tis_core_init(struct device *dev
} else {
tpm_tis_probe_irq(chip, intmask);
}
- tpm_chip_stop(chip);
}

rc = tpm_chip_register(chip);