[LinuxBIOS] mcp55 flashrom problem

Ulf Jordan jordan at chalmers.se
Mon Mar 5 22:31:41 CET 2007


On Mon, 5 Mar 2007, Ward Vandewege wrote:

> On Mon, Mar 05, 2007 at 05:53:52PM +0100, Carl-Daniel Hailfinger wrote:
>> A counter with 6 bits per byte and one unknown byte. Note how no
>> value is >=0x40 and a wraparound of the second value increases
>> the third value by 1?
>> Could be a timer, e.g. boot time or something like that. Try
>> to correlate boot time intervals with the differences in the
>> counter.

Hypothesis: boot or shutdown time in UTC and date (Ward's local time seems 
to be -0500 from UTC, translation to decimal below):

>                 -0000fd90  0f 00 24 00 12 00 00 02  03 07 00 00 40 00 00 00
The baseline was last Friday, i.e 2007-03-02:     02  03 07
> 2007-03-05 10:17 +0000fd90  0a 00 00 00 0f 00 00 05  03 07 00 00 40 00 00 00
                               ss    mm    hh       DD  MM YY
                               10    00    15       05  05 07
> 2007-03-05 10:29 +0000fd90  16 00 1c 00 0f 00 00 05  03 07 00 00 40 00 00 00
                               22    28    15
> 2007-03-05 10:38 +0000fd90  14 00 25 00 0f 00 00 05  03 07 00 00 40 00 00 00
                               20    37    15
> 2007-03-05 10:40 +0000fd90  14 00 27 00 0f 00 00 05  03 07 00 00 40 00 00 00
                               20    39    15
> 2007-03-05 10:42 +0000fd90  08 00 29 00 0f 00 00 05  03 07 00 00 40 00 00 00
                               08    41    15
> 2007-03-05 10:43 +0000fd90  39 00 2a 00 0f 00 00 05  03 07 00 00 40 00 00 00
                               57    42    15
> 2007-03-05 10:48 +0000fd90  2e 00 2c 00 0f 00 00 05  03 07 00 00 40 00 00 00
                               46    44    15
> 2007-03-05 10:50 +0000fd90  16 00 31 00 0f 00 00 05  03 07 00 00 40 00 00 00
                               22    49    15
> 2007-03-05 10:52 +0000fd90  0b 00 33 00 0f 00 00 05  03 07 00 00 40 00 00 00
                               11    51    15
> 2007-03-05 10:53 +0000fd90  00 00 35 00 0f 00 00 05  03 07 00 00 40 00 00 00
                               00    53    15
> 2007-03-05 10:55 +0000fd90  32 00 36 00 0f 00 00 05  03 07 00 00 40 00 00 00
                               50    54    15
> 2007-03-05 10:57 +0000fd90  28 00 38 00 0f 00 00 05  03 07 00 00 40 00 00 00
                               40    56    15
> 2007-03-05 11:00 +0000fd90  0e 00 3b 00 0f 00 00 05  03 07 00 00 40 00 00 00
                               14    59    15
> 2007-03-05 11:02 +0000fd90  05 00 01 00 10 00 00 05  03 07 00 00 40 00 00 00
                               05    01    16
> 2007-03-05 11:03 +0000fd90  36 00 02 00 10 00 00 05  03 07 00 00 40 00 00 00
                               54    02    16
> 2007-03-05 11:05 +0000fd90  2c 00 04 00 10 00 00 05  03 07 00 00 40 00 00 00
                               44    04    16
> 2007-03-05 13:01 +0000fd90  22 00 3b 00 11 00 00 05  03 07 00 00 40 00 00 00
                               34    59    17
> These timestamps are the ones of the rom files; the actual boot time would be
> 30-60 seconds earlier.
>
> The boot at 2007-03-05 10:17 was a cold boot.
>
> The boot at 2007-03-05 11:00 was a cold boot.
>
> The boot at 2007-03-05 13:01 was a *really* cold boot: I unplugged power,
> waited 10 seconds, and then replugged and started the machine.

Was the down time (from shutdown to power on) like a few seconds/minutes 
or longer? I try to distinguish between last *shutdown* time and last 
*boot* time.

For the boot 2007-03-05 10:17, there is a 16 minute difference, if we 
interpret the numbers in the image as time in UTC, for 2007-03-05 10:48 a 
4 minute difference, while for the others more like within one minute. 
This suggest that it could be correlated with last shutdown time.

A possible experiment to distinguish between shutdown and boot time could 
be to do dumps after a 10 minute shutdown and a 1 minute shutdown. If 
the interpreted time in the image differs by approximately 10 minutes in 
the first case, I believe we have shown it to be the shutdown time.

/ulf




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