Yes, it seems that is the case and we were totally unable to use tboot on our HP systems. Christian’s patch at least got things working and it is possible there are other systems out there that have the same problem. If you have another solution in mind that is fine (perhaps making it configurable) but there should be a way for folks to work around problems in the TPM hardware like this.





From: Wang, Shane []
Sent: Monday, February 01, 2010 6:33 AM
To: Ross Philipson;
Cc: Christian Limpach
Subject: RE: [tboot-devel] [PATCH] Fix timeout bug introduced by tboot.hg changeset 176.


Hi, Ross and Christian,


According to TCG PC Client Sepcific TPM Interface Specification (TIS), calling the TPM_GetCapability command with the capability TPM_CAP_PROP_TIS_TIMEOUTS return an array of uint32 values each representing the number of microseconds for the associated timeout. And the structure we used represents the number of milliseconds. I also tested the code with some TPMs. I guess maybe your hp6930p doesn't conform to the spec.





From: Ross Philipson []
Sent: 2010
129 18:45
Cc: Christian Limpach
Subject: [tboot-devel] [PATCH] Fix timeout bug introduced by tboot.hg changeset 176.

Patch to fix timeout bug introduced by tboot.hg changeset 176. Either the TPM in the hp6930p doesn't operate to spec or the code was never tested.  With the patch, the values read from the tpm are equal to the default values used before tpm timeout code was added in changesets 163 and 176.


Signed-off-by: Christian Limpach

Acked-by: Ross Philipson



diff -r 75e242a56344 tboot/common/tpm.c

--- a/tboot/common/tpm.c      Tue Jan 05 23:05:07 2010 -0800

+++ b/tboot/common/tpm.c      Fri Jan 29 00:59:05 2010 +0000

@@ -1944,10 +1944,10 @@

          * timeout_x represents the number of milliseconds for the timeout

          * and timeout[x] represents the number of microseconds.


-        g_timeout.timeout_a = timeout[0]/1000;

-        g_timeout.timeout_b = timeout[1]/1000;

-        g_timeout.timeout_c = timeout[2]/1000;

-        g_timeout.timeout_d = timeout[3]/1000;

+        g_timeout.timeout_a = timeout[0];

+        g_timeout.timeout_b = timeout[1];

+        g_timeout.timeout_c = timeout[2];

+        g_timeout.timeout_d = timeout[3];

         printk("TPM timeout values: A: %u, B: %u, C: %u, D: %u¥n",

                g_timeout.timeout_a, g_timeout.timeout_b, g_timeout.timeout_c,