602
HyperTransport
™
Link
Frequency
Changes
May
Cause
a
System
Hang
Description
A
HyperTransport
™
link
operating
at
a
Gen
3
frequency
(
greater
than
2.0
GT
/
s
)
may
have
excessive
link
retries
or
may
fail
to
train
after
transitioning
to
a
new
Gen
3
frequency
.
The
failure
is
due
to
a
misconfiguration
of
the
HyperTransport
Link
Phy
Receiver
DLL
Control
and
Test
5
Register
[
DllProcessFreqCtlOverride
,
DllProcessFreqCtlIndex
2]
settings
(
D
18
F
4
x
1[9
C
,94,8
C
,84]_
x
[5:4][9:0][8,0]
F
_
dm
[1]
bits
12
and
3:0).
These
settings
are
specific
to
each
Gen
3
frequency
and
may
be
programmed
only
while
the
link
is
operating
at
a
Gen
1
frequency
(
less
than
or
equal
to
2.0
GT
/
s
).
Potential
Effect
on
System
System
hang
.
Suggested
Workaround
Software
that
transitions
a
HyperTransport
link
between
two
different
Gen
3
frequencies
must
first
transition
the
link
to
a
Gen
1
frequency
so
that
the
DllProcessFreqCtlOverride
and
DllProcessFreqCtlIndex
2
settings
may
be
programmed
according
to
the
algorithm
documented
in
the
BIOS
and
Kernel
Developer's
Guide
(
BKDG
)
for
AMD
Family
15
h
Models
00
h-
0
Fh
Processors
,
order
# 42301.
Fix
Planned
No
fix
planned
Revision
Guide
for
AMD
Family
15
h
Models
00
h-
0
Fh
Processors
48063
Rev
. 3.18
October
2012
40
Product
Errata