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 would be very surprised if polling the TIS status register effects. Well, I was surprised too, but given the patch that's causing the problem, it was the only explanation I could come up with. > the firmware running inside the chip.. > > > BTW, no interrupt in your latop setup? I'm surprised by that.. Heh, I hear rumours that most laptops are delivered like this and a large software company might be annoyed enough about the problem to mandate interrupts the next time it produces a hardware requirements spec. James
