On Wed, Jul 11, 2018 at 12:08:53PM -0700, James Bottomley wrote: > On Wed, 2018-07-11 at 12:21 -0600, Jason Gunthorpe wrote: > > On Wed, Jul 11, 2018 at 10:11:14AM -0700, James Bottomley wrote: > > > tpm_tis regressed recently to the point where the TPM being driven > > > by > > > it falls off the bus and cannot be contacted after some hours of > > > use. > > > This is the failure trace: > > > > > > jejb@jarvis:~> dmesg|grep tpm > > > [ 3.282605] tpm_tis MSFT0101:00: 2.0 TPM (device-id 0xFE, rev-id > > > 2) > > > [14566.626614] tpm tpm0: Operation Timed out > > > [14566.626621] tpm tpm0: tpm2_load_context: failed with a system > > > error -62 > > > [14568.626607] tpm tpm0: tpm_try_transmit: tpm_send: error -62 > > > [14570.626594] tpm tpm0: tpm_try_transmit: tpm_send: error -62 > > > [14570.626605] tpm tpm0: tpm2_load_context: failed with a system > > > error -62 > > > [14572.626526] tpm tpm0: tpm_try_transmit: tpm_send: error -62 > > > [14577.710441] tpm tpm0: tpm_try_transmit: tpm_send: error -62 > > > ... > > > > > > The problem is caused by a change that caused us to poke the TPM > > > far > > > more often to see if it's ready. Apparently something about the > > > bus > > > its on and the TPM means that it crashes or falls off the bus if > > > you > > > poke it too often and once this happens, only a reboot will recover > > > it. > > > > I wonder if something about triggering ETIME even once breaks the > > driver so it can't talk to the chip at all thereafter.. > > > > Ie it doesn't abort the command properly and becomes desynced with > > the TIS execution protocol. > > Yes, I wondered about this, but I don't understand the bus protocol > well enough. The tpm-interface:tpm_try_transmit() which throws the > first ETIME says after we get that we send chip->ops->cancel() which > tpm_tis simply translates to tpm_tis_ready() which also times out. Is > there a bigger hammer I can hit it with? I don't remember off hand.. But this is, IMHO, a better guess than the firmware crashes from reading the status register.. Perhaps reducing the timeout to force a ETIME would prove the theory? Jason
