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On 03/07/2018 07:24 PM, Stephen Douthit wrote:
On 03/07/2018 12:41 PM, Kevin O'Connor
> On Wed, Mar 07, 2018 at 12:33:36PM -0500, Stephen Douthit wrote:
>> On 03/07/2018 10:33 AM, Paul Menzel wrote:
Am Dienstag, den 06.03.2018, 11:57 -0500 schrieb Stephen Douthit:
>>> On 03/06/2018 11:04 AM, Paul Menzel wrote:
>>>> On 03/02/18 17:31, Kevin O'Connor wrote:
>>>>> On Tue, Feb 27, 2018 at 02:17:08PM -0500, Stephen Douthit wrote:
>>>>> Thanks. I committed this series.
>>>> The second commit introduced a regression with coreboot on the
>>>> ASRock E350M1. There are a bunch of time-outs, causing the startup
>>>> to be really slow. With no serial console, the user thinks, it’s
>>>> not working and start to debug.
>>> Looking through the the user manual for that board I don't see that it
>>> has a TPM, or even the header for one, so a timeout seems correct.
>> Indeed, no TPM is present.
> Thanks for confirming.
>>> Multiple 750ms timeouts does seem pretty painful though. I hadn't
>>> considered that tis_probe() would be called multiple times if no TPM
>>> was present.
>>> What's the preferred way to have a probe function run and bail before
>>> rerunning the timeout? Just put a static flag in tis_probe()? The
>>> attached patch takes that approach. Please let me know if that fixes
>>> the issue for you, or if there's some other preferred pattern I should
>>> use here.
>> Unfortunately, that didn’t help.
>> $ git log --oneline -2
>> fd1cbb4 (HEAD -> master, origin/master, origin/HEAD) tpm: Save tis_probe()
result to avoid a reun of lengthy timeouts
>> 5adc8bd tpm: Handle unimplemented TIS_REG_IFACE_ID in tis_get_tpm_version()
>> And the time-outs seem to be around 20 seconds or more. Please find the
>> log with time stamps attached (`sudo ./readserial.py /dev/ttyUSB0`).
> Yikes, 20 seconds is the medium duration timeout, not the default A
> timeout of 750ms. I was poking the wrong area with the last patch.
> It looks like tis_probe() is propagating the return from
> tis_wait_access() in the no device present case.
FYI, even adding 5ms to the boot time is unacceptable. Is there
anyway to verify the hardware exists before waiting for it to be
The only way I know of would be to check if we have TCPA or TPM2 ACPI
tables, and only attempt to probe for a TPM if those are present.
Attached patch should do that, and it's probably a good idea
independent of any of my other patches.
I applied both the latest commits, and quickly testing that, I believe the long delay is
still there. I won’t be able to get to until next week, and make the ACPI tables
available. Maybe there is a way to test this with QEMU? Kevin also owns the ASRock E350M1
to my knowledge.
Thanks for the continued testing. I don't have a good theory for
what's going on at the moment.
It looks like there's a series resistor I can depop to isolate the TPM
reset on the board I was testing on. I should be able to jumper that
so I can test the TPM and no-TPM cases on the same hardware.
Hopefully I can reproduce the timeout that way.