Date:	Mon, 28 Mar 2011 20:19:00 -0400
From:	Stefan Berger <stefanb@...ux.vnet.ibm.com>
To:	Jeff Layton <jlayton@...chiereds.net>
CC:	linux-kernel@...r.kernel.org, tpmdd-devel@...ts.sourceforge.net
Subject: Re: TPM chip prevents machine from suspending

On 03/28/2011 07:10 PM, Stefan Berger wrote:
> On 03/28/2011 03:45 PM, Jeff Layton wrote:
>> On Mon, 28 Mar 2011 14:12:41 -0400
>> Jeff Layton<jlayton@...chiereds.net>  wrote:
>>
>>> On Mon, 28 Mar 2011 13:25:06 -0400
>>> Stefan Berger<stefanb@...ux.vnet.ibm.com>  wrote:
>>>
>>>> On 03/28/2011 10:08 AM, Jeff Layton wrote:
>>>>> My wife's machine apparently has a TPM chip in it. Since I 
>>>>> upgraded it
>>>>> to Fedora 14, it fails to suspend consistently. On the first 
>>>>> attempt to
>>>>> suspend it, it works fine. Once it has woken back up however, it will
>>>>> not suspend again. Here's the dmesg log from such an attempt:
>>>>>
>>>>> [  202.460967] PM: Syncing filesystems ... done.
>>>>> [  202.464818] PM: Preparing system for mem sleep
>>>>> [  202.485968] Freezing user space processes ... (elapsed 0.01 
>>>>> seconds) done.
>>>>> [  202.497079] Freezing remaining freezable tasks ... (elapsed 
>>>>> 0.01 seconds) done.
>>>>> [  202.508067] PM: Entering mem sleep
>>>>> [  202.508086] Suspending console(s) (use no_console_suspend to 
>>>>> debug)
>>>>> [  202.508451] sd 3:0:0:0: [sdb] Synchronizing SCSI cache
>>>>> [  202.508562] sd 2:0:0:0: [sda] Synchronizing SCSI cache
>>>>> [  202.508616] sd 3:0:0:0: [sdb] Stopping disk
>>>>> [  202.511956] parport_pc 00:0b: disabled
>>>>> [  202.512127] serial 00:09: disabled
>>>>> [  202.512134] serial 00:09: wake-up capability disabled by ACPI
>>>>> [  202.536058] legacy_suspend(): pnp_bus_suspend+0x0/0x82 returns 38
>>>>> [  202.536061] PM: Device 00:02 failed to suspend: error 38
>>>>> [  202.997517] sd 2:0:0:0: [sda] Stopping disk
>>>>> [  202.997806] PM: Some devices failed to suspend
>>>>> [  202.998085] sd 2:0:0:0: [sda] Starting disk
>>>>> [  202.998144] sd 3:0:0:0: [sdb] Starting disk
>>>>> [  202.998614] serial 00:09: activated
>>>>> [  202.999158] parport_pc 00:0b: activated
>>>>> [  204.543094] PM: resume of devices complete after 1545.282 msecs
>>>>> [  204.543268] PM: Finishing wakeup.
>>>>> [  204.543270] Restarting tasks ... done.
>>>>>
>>>>> ...error 38 is ENOSYS, and the 00:02 is this:
>>>>>
>>>>> # cat /sys/bus/pnp/devices/00\:02/id
>>>>> IFX0102
>>>>> PNP0c31
>>>> Also the tpm_tis driver handles both of these. Can you confirm which
>>>> module that laptop was using  (tpm_tis or tpm_infineon) and try 
>>>> whether
>>>> one of them works better than the other one? Please do a reboot 
>>>> between
>>>> trying one and then the other.
>>>>
>>> It's using tpm_tis:
>>>
>>> lrwxrwxrwx. 1 root root 0 Mar 28 13:40 
>>> /sys/bus/pnp/devices/00:02/driver ->  ../../../bus/pnp/drivers/tpm_tis
>>>
>>> FWIW, the fedora kernels have this:
>>>
>>> CONFIG_TCG_TPM=y
>>> CONFIG_TCG_TIS=y
>>> CONFIG_TCG_NSC=m
>>> CONFIG_TCG_ATMEL=m
>>> CONFIG_TCG_INFINEON=m
>>>
>>> When I boot, tpm_infineon is also plugged in, but I can remove that
>>> module and nothing seems to change (not sure what's plugging it in).
>>>
>>> I can try using tpm_infineon, but I'm not sure how to disable tpm_tis
>>> with it compiled in like this -- is that possible?
>>>
>>>> Try the following before and after a suspend/resume:
>>>>
>>>> cd /sys
>>>> find . | grep caps$ | xargs cat
>>>>
>>>> It should display manufacturer data.
>>>>
>>> There's only one "caps" file. Here's the before (after a fresh reboot):
>>>
>>> # cat ./devices/pnp0/00:02/caps
>>> Manufacturer: 0x49465800
>>> TCG version: 1.2
>>> Firmware version: 1.0
>>>
>>> ...after a successful suspend/resume cycle:
>>>
>>> # cat ./devices/pnp0/00:02/caps
>>>
>>> ...it gives no output at all. Guess that lends some weight to the
>>> theory of it not being reset properly on resume?
>>>
>>> Thanks for the help so far...
>> FWIW, I turned up dynamic debugging on the tpm files and got this in
>> the ring buffer when I tried to read from "caps":
>>
>> [ 6880.495071] tpm_tis 00:02: A TPM error (38) occurred attempting to 
>> determine the manufacturer
>>
>> I don't see any obvious places that return ENOSYS in the tpm code, so
>> I'm not clear on where that's coming from...
>>
> Ok, so this error code means TPM_INVALID_POSTINIT  (not a posix code) 
> and means that this command was received in the wrong sequence 
> relative to a TPM_Startup command. Well, what's supposed to be 
> happening is this:
>
> When the machines (S3) suspends then the OS needs to send a 
> TPM_SaveState() to the TPM. This is done by the Linux driver. Once the 
> VM resumes, the BIOS is supposed to send a TPM_Startup(ST_STATE) to 
> the TPM.
>
> Now the fun starts when a BIOS isn't doing that (even though the spec 
> says it's supposed to), which could very well be the case in your case 
> (don't know what broken BIOSes are out there...  Did it ever work 
> before with the TPM driver in the kernel ?). I could try to send you a 
> small tool that you would have to run from user space upon resume so 
> that we can see that this error goes away. If that's verified we could 
> subsequently write a patch for the TPM driver to also send the 
> TPM_Startup(ST_STATE) to the TPM, which then in the case of most 
> BIOSes would be the 2nd time that the TPM receives such a command. I 
> think TPMs should be able to digest this 2nd TPM_Startup() well, but 
> I'd have to check -- but really we would ill-fix it just because of 
> one (possibly) buggy BIOS.
>
> The failure of the 2nd suspend then likely stems from the TPM not 
> accepting the TPM_SaveState() anymore since it hasn't seen the 
> TPM_Startup(ST_STATE) that we expected the BIOS to send.
>
> Another possibility would be for you to check for BIOS updates from 
> the laptop manufacturer...
>
So here is this tool:

#include <stdio.h>
#include <stdint.h>
#include <fcntl.h>
#include <unistd.h>

int main(void) {
     const uint8_t startup_st_state[] = {
         0x00, 0xc1,
         0x00, 0x00, 0x00, 0x0c,
         0x00, 0x00, 0x00, 0x99,
         0x00, 0x02
     };
     uint8_t buf[10];
     int fd = open("/dev/tpm0", O_RDWR);
     int len;
     uint32_t err;

     if (fd < 0) {
         printf("Could not open /dev/tpm0\n");
         return 1;
     }

     len = write(fd, startup_st_state, sizeof(startup_st_state));

     if (len != sizeof(startup_st_state)) {
         printf("Write failed.\n");
         goto err_exit;
     }

     len = read(fd, buf, sizeof(buf));

     if (len != sizeof(buf)) {
         printf("Expected %d bytes bot got %d\n", (int)sizeof(buf), len);
         goto err_exit;
     }

     if (buf[1] != 0xc4) {
         printf("Response tag is bad.\n");
         goto err_exit;
     }

     if (buf[5] != sizeof(buf)) {
         printf("Response length is bad: %d\n", buf[5]);
         goto err_exit;
     }

     err = buf[6] << 24 | buf[7] << 16 | buf[8] << 8 | buf[9];
     if (err) {
         printf("Got an error code in response: %u\n", err);
     } else {
         printf("Success!\n");
     }

err_exit:
     close(fd);
     return 0;
}

gcc startup.c -o startup

Run it as 'root' after a resume and if that works do the 'cat ...' again.

    Stefan

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