On Mon, Apr 27, 2015 at 12:29 PM, Matt DeVillier <matt.devill...@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 -duncan > Thanks, > > Paul > > > [1] > http://review.coreboot.org/gitweb?p=board-status.git;a=commitdiff;h=3926f95b143b74c0762516df0bdf250c1dd8ba32#patch4 > [2] http://review.coreboot.org/4375 > > > > > > -- > coreboot mailing list: coreboot@coreboot.org > http://www.coreboot.org/mailman/listinfo/coreboot >
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