On 07-03-18 09:41, Thiebaud Weksteen wrote:

Thanks for testing and sending this report! This patch relies heavily on
the functions exposed by the firmware. My first guess would be that some of
these may not be implemented correctly by the manufacturer.

Could you share more information on this specific device?

I've the same device as Jeremy, but I just tried a 4.16-rc3 kernel
and I'm not seeing this problem, BIOS settings all default (I loaded
the BIOS defaults to make sure).

Do you have any link to the manufacturer website (I found [1] but it is
based on an ARM CPU)?
Do you have the option to update your firmware? Is a copy of the firmware
available from the manufacturer?

This is a really cheap Windows tablet which was given away for free in
the Netherlands with some home-schooling language courses, or something

Both mine and Jeremy tablets come from a website in the Netherlands
where people can buy/sell used goods.

Most relevant for this discussion I guess is that this device is
based on a Bay Trail Z3735G SoC, on which according to the internets:

The TPM 2.0 it contains is implemented as part of the TXE firmware.

Since I cannot reproduce I'm thinking that maybe Jeremy actually has
some log messages in the TPM log, where as mine is empty.  Is there a
way to make sure some messages are in there?



On your side, I assume no error message got displayed on the screen when
booting. Would you be able to try to boot in an UEFI shell [2] and execute
the command "dh -v"?


[1] https://www.gp-electronic.nl/product/7inchtablet

On Tue, Mar 6, 2018 at 5:00 PM Jeremy Cline <jer...@jcline.org> wrote:

Hi folks,

Commit 33b6d03469b2 ("efi: call get_event_log before ExitBootServices")
causes my GP-electronic T701 tablet to hang when booting. Reverting the
patch series or hiding the TPM in the BIOS fixes the problem.

I've never fiddled with TPMs before so I'm not sure what what debugging
information to provide. It's got an Atom Z3735G and the UEFI firmware is
InsydeH20 version BYT70A.YNCHENG.WIN.007.

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