[coreboot] DDR fails on F2A85-M

David Hubbard david.c.hubbard+coreboot at gmail.com
Wed May 22 03:19:01 CEST 2013


> > If DDR3-667 works but AGESA fails at DDR3-1600, is it possible to go
back
> > to DDR3-667 or try an intermediate speed, say DDR3-1333 ?
>
> Maybe there is an option in AGESA where you can limit the maximum
> frequency.
>
> $ more src/mainboard/asus/f2a85-m/buildOpts.c
> […]
> #define BLDCFG_MEMORY_BUS_FREQUENCY_LIMIT         DDR1866_FREQUENCY
> […]
> #define BLDCFG_MEMORY_CLOCK_SELECT                DDR1600_FREQUENCY
> […]

This is a great suggestion.

I have spent a few days studying the AGESA code to find out what
frequencies it tries. I concluded that the built-in AGESA autodetection is
very limited. It may be there is a bug in the AGESA autodetection because
this is not the same code path generally used in vendor BIOSes. The error
messages about missing tables are suspicious. I believe it means AMD has
the motherboard OEM (i.e. Asus) provide parameter tables measured with a
scope that help the timings match the production board.

Specifically I added IDS_HDT_CONSOLE (MEM_FLOW, "MemPPSCFlow enter "
__FILE__ ":%d\n", __LINE__); and IDS_HDT_CONSOLE (MEM_FLOW, "MemPPSCFlow
exit " __FILE__ ":%d\n", __LINE__); to the function MemPPSCFlow() in
src/vendorcode/amd/agesa/f15tn/Proc/Mem/Ps/mp.c



I attempted setting BLDCFG_MEMORY_BUS_FREQUENCY_LIMIT and
BLDCFG_MEMORY_CLOCK_SELECT:
diff --git a/src/mainboard/asus/f2a85-m/buildOpts.c
b/src/mainboard/asus/f2a85-m/buildOpts.c
index 7f893f9..b9346b7 100644
--- a/src/mainboard/asus/f2a85-m/buildOpts.c
+++ b/src/mainboard/asus/f2a85-m/buildOpts.c
@@ -102,7 +102,7 @@

 #define BLDCFG_AMD_PLATFORM_TYPE                  AMD_PLATFORM_MOBILE

-#define BLDCFG_MEMORY_BUS_FREQUENCY_LIMIT         DDR1866_FREQUENCY
+#define BLDCFG_MEMORY_BUS_FREQUENCY_LIMIT         DDR1333_FREQUENCY
 #define BLDCFG_MEMORY_MODE_UNGANGED               TRUE
 #define BLDCFG_MEMORY_QUAD_RANK_CAPABLE           TRUE
 #define BLDCFG_MEMORY_QUADRANK_TYPE               QUADRANK_UNBUFFERED
@@ -116,8 +116,8 @@
 #define BLDCFG_POWER_DOWN_MODE                    POWER_DOWN_BY_CHIP_SELECT
 #define BLDCFG_ONLINE_SPARE                       FALSE
 #define BLDCFG_BANK_SWIZZLE                       TRUE
-#define BLDCFG_TIMING_MODE_SELECT                 TIMING_MODE_AUTO
-#define BLDCFG_MEMORY_CLOCK_SELECT                DDR1600_FREQUENCY
+#define BLDCFG_TIMING_MODE_SELECT                 TIMING_MODE_LIMITED
+#define BLDCFG_MEMORY_CLOCK_SELECT                DDR1333_FREQUENCY
 #define BLDCFG_DQS_TRAINING_CONTROL               TRUE
 #define BLDCFG_IGNORE_SPD_CHECKSUM                FALSE
 #define BLDCFG_USE_BURST_MODE                     FALSE

I then ran make clean; make and tried booting coreboot, but hit the same
error (ASSERTION FAILED mmExcludeDimm.c line 26). I'm going to keep trying
lower speeds.

I also attemped configuring coreboot with 1.65V though my memory is only
rated to 1.60V. I checked with the vendor BIOS that the memory is at least
bootable at 1.65V. Then I tried booting coreboot at 1.65V (without the
previous memory bus limit), but it stopped at the same assertion.


> Could you try to find out with `bios_extract` for example what AGESA
> version the vendor BIOS uses.

I have not had time to run bios_extract but I did identify that the BIOS
file supplied on Asus' website for the F2A85-M/CSM is identical to the data
on the chip after stripping the first 2048 bytes. For example:

dd if=f2a85-m-asus-5103-2012.09.10.v2.10.1208.cap of=f2a85-flashrom.bin
bs=2048 skip=1


> PS: David, Google Mail changed the compose interface and they send HTML
> message in addition to text by default. Could you change that to just
> plain text please [3][4]?

I think this is now plain-text only, please let me know if gmail sends it
as HTML. Sorry!
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