On my old C720 Chromebook, in the past I have needed to add `GRUB_CMDLINE_LINUX_DEFAULT="tpm_tis.force=1"` to GRUB to enable suspend/resume to work properly in Debian.
After a fresh re-install and upgrade to Debian unstable/sid, suspend/resume is not working with kernel 5.2.9-2. System will suspend, but trying to resume results in a hard reboot. I think the problem is with tpm_tis.
Messages in the log upon boot ...
```
$ journalctl -b | grep tpm
Sep 16 18:18:01 cruithne kernel: tpm_tis tpm_tis: 1.2 TPM (device-id 0xB, rev-id 16)
Sep 16 18:18:01 cruithne kernel: tpm tpm0: tpm_try_transmit: send(): error -5
Sep 16 18:18:01 cruithne kernel: tpm tpm0: A TPM error (-5) occurred attempting to determine the timeouts
Sep 16 18:18:01 cruithne kernel: tpm_tis tpm_tis: Could not get TPM timeouts and durations
Sep 16 18:18:01 cruithne kernel: tpm_tis 00:08: 1.2 TPM (device-id 0xB, rev-id 16)
Sep 16 18:18:01 cruithne kernel: tpm tpm0: tpm_try_transmit: send(): error -5
Sep 16 18:18:01 cruithne kernel: tpm tpm0: A TPM error (-5) occurred attempting to determine the timeouts
Sep 16 18:18:01 cruithne kernel: tpm_tis 00:08: Could not get TPM timeouts and durations
Sep 16 18:18:01 cruithne kernel: tpm_inf_pnp 00:08: Found TPM with ID IFX0102
```
Suspend/resume *does* continue to work with kernel 4.19.67-2 (current default in Debian stable). Messages in the log ...
```
Sep 16 18:00:38 cruithne kernel: tpm_tis 00:08: 1.2 TPM (device-id 0xB, rev-id 16)
Sep 16 18:00:38 cruithne kernel: tpm tpm0: [Firmware Bug]: TPM interrupt not working, polling instead
```
Removing the "tpm_tis.force=1" line from GRUB when booting into kernel 5.2.9-2 makes no difference.
A google search with "tpm tpm0" "tpm_try_transmit" "error -5" "A TPM error (-5) occurred attempting to determine the timeouts" returns NO hits. Dropping the last term is a bit more successful but still leads me to no solution.
Any ideas how I might get this to work with the latest kernel 5.2*? Thanks in advance!
--