[coreboot] Google Panther: coreboot has to wait for Intel’s ME (Management Engine)

[Berth-Olof Bergman]

That’s truly amazing! So the FSP + coreboot part only takes a quarter of a second? Intel FSP must be on steroids!!

The total boot time is the sum of components time, so if you fix that problem you will have close to a quarter of second boot time!! Can we see a video clip of that boot?

> 27 apr 2015 kl. 22:42 skrev Duncan Laurie <dlaurie at chromium.org>:
> 
> On Mon, Apr 27, 2015 at 12:29 PM, Matt DeVillier <matt.devillier at gmail.com <mailto:matt.devillier at gmail.com>> wrote:
> On 4/26/2015 3:03 AM, Paul Menzel wrote:
>> Dear coreboot folks,
>> 
>> 
>> looking at the time stamps of the Intel Haswell device Google Panther,
>> which Matt DeVillier thankfully uploaded to the board status repository
>> [1], it looks odd that it took around a quarter of a second, from after
>> the SeaBIOS payload was decompressed to starting the payload. This is
>> almost half of the whole boot time.
>> 
>>         […]
>>           90:load payload                                      233,302 (216)
>>           15:starting LZMA decompress (ignore for x86)         233,415 (113)
>>           16:finished LZMA decompress (ignore for x86)         250,327 (16,912)
>>           99:selfboot jump                                     493,712 (243,384)
>> 
>> Thanks to Aaron Durbin’s analysis of the code path, the finalize in line
>> 138 of `src/southbridge/intel/lynxpoint/smi.c` calls
>> `intel_me_mbp_clear()` in line 589 of
>> `src/southbridge/intel/lynxpoint/me_9.x.c`.
>> 
>>         $ more src/southbridge/intel/lynxpoint/me_9.x.c # line 589
>>         […]
>>         #if CONFIG_ME_MBP_CLEAR_LATE
>>         	/* Wait for ME MBP Cleared indicator */
>>         	intel_me_mbp_clear(PCH_ME_DEV);
>>         #endif
>>         […]
>> 
>> The issue is even described in the Kconfig option description of
>> `ME_MBP_CLEAR_LATE` and the commit message of commit 3d299c4b (lynxpoint
>> me: add support for mbp clear wait in finalize step) [2] adding this
>> option.
>> 
>>         $ more src/southbridge/intel/lynxpoint/Kconfig
>>         […]
>>         config ME_MBP_CLEAR_LATE
>>         	bool "Defer wait for ME MBP Cleared"
>>         	default y
>>         	help
>>         	  If you set this option to y, the Management Engine driver
>>         	  will defer waiting for the MBP Cleared indicator until the
>>         	  finalize step.  This can speed up boot time if the ME takes
>>         	  a long time to indicate this status.
>>         […]
>> 
>> I guess there is no way to get fixed ME BLOBs from Intel. I heard the ME
>> BLOB has been fixed for newer Intel devices.
> 
> The ME firmware that ships with Panther is 9.5.13.1706.  I've also tested 9.5.41.1904 (what I'm using in the firmware referenced above) and 9.5.45.1922 (which I just came across today) - all display the same behavior in terms of time needed to report MBP cleared.  The 9.6 series ME firmware is also for Haswell/Lynxpoint, but I'm unsure if it's compatible with systems shipped with ME 9.5.  Since I have an external programmer, I suppose I could always give it a try :)  The 10.0 series ME firmware is for Broadwell and is more likely to contain the fix, but less likely to be compatible with Haswell/LP.
> 
> -Matt
> 
> 
> 
> 
> Unfortunately the wait for ME MBP to clear is even worse on Broadwell, but with ME10 there is a (gross) boot flow to avoid it thanks to some new commands that do not need acknowledgement:
> 
> http://review.coreboot.org/gitweb?p=coreboot.git;a=commit;h=c99681f4f23ddacd64fddbedf060f6443d008090 <http://review.coreboot.org/gitweb?p=coreboot.git;a=commit;h=c99681f4f23ddacd64fddbedf060f6443d008090>
> 
> -duncan
>  
>> Thanks,
>> 
>> Paul
>> 
>> 
>> [1] http://review.coreboot.org/gitweb?p=board-status.git;a=commitdiff;h=3926f95b143b74c0762516df0bdf250c1dd8ba32#patch4 <http://review.coreboot.org/gitweb?p=board-status.git;a=commitdiff;h=3926f95b143b74c0762516df0bdf250c1dd8ba32#patch4>
>> [2] http://review.coreboot.org/4375 <http://review.coreboot.org/4375>
>> 
>> 
> 
> 
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