AMD 3200 Revision History - Page 55

Processor, Generate, Incorrect, P-state, Limit, Interrupts

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48063 Rev. 3.18 October 2012 Revision Guide for AMD Family 15h Models 00h-0Fh Processors 667 Processor May Generate Incorrect P-state Limit Interrupts Description P-state limit changes due to SB-RMI (SBI P-state Limit[PstateLimit], MSRC001_0072[10:8]), software (Software P-state Limit Register[SwPstateLimit], D18F3x68[30:28]), or hardware thermal control (entering HTC-active state, i.e. PROCHOT# assertion) may generate duplicate interrupts when Hardware Thermal Control Register bits [PslApicLoEn, PslApicHiEn] are not both zero (D18F3x64[7:6] != 00b). The processor actually uses APM TDP Control[ApmTdpLimitIntEn] = 1b to enable the generation of interrupts for P-state limit changes due to SB-RMI, software, or HTC, as well as to generate interrupts for changes to TDP Limit 3 Register[ApmTdpLimit] (D18F5xE8[28:16]). Potential Effect on System Operating systems monitoring processor P-state capabilities may receive duplicate notification of P-state limit changes due to SB-RMI, software, or HTC. Suggested Workaround BIOS should leave Hardware Thermal Control[PslApicLoEn, PslApicHiEn] at their default reset value (D18F3x64[7:6] = 00b) and should set APM TDP Control[ApmTdpLimitIntEn] (D18F4x16C[4]) = 1b. This workaround requires software to receive both P-state limit change interrupts and ApmTdpLimit change interrupts. Fix Planned No fix planned Product Errata 55

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667
Processor
May
Generate
Incorrect
P-state
Limit
Interrupts
Description
P-state
limit
changes
due
to
SB-RMI
(
SBI
P-state
Limit
[
PstateLimit
],
MSRC
001_0072[10:8] ,
software
(
Software
P-state
Limit
Register
[
SwPstateLimit
],
D
18
F
3
x
68[30:28] ,
or
hardware
thermal
control
(
entering
HTC-active
state
,
i
.
e
.
PROCHOT
#
assertion
may
generate
duplicate
interrupts
when
Hardware
Thermal
Control
Register
bits
[
PslApicLoEn
,
PslApicHiEn
]
are
not
both
zero
(
D
18
F
3
x
64[7:6] != 00
b
.
The
processor
actually
uses
APM
TDP
Control
[
ApmTdpLimitIntEn
] = 1
b
to
enable
the
generation
of
interrupts
for
P-state
limit
changes
due
to
SB-RMI
,
software
,
or
HTC
,
as
well
as
to
generate
interrupts
for
changes
to
TDP
Limit
3
Register
[
ApmTdpLimit
] (
D
18
F
5
xE
8[28:16] .
Potential
Effect
on
System
Operating
systems
monitoring
processor
P-state
capabilities
may
receive
duplicate
notification
of
P-state
limit
changes
due
to
SB-RMI
,
software
,
or
HTC
.
Suggested
Workaround
BIOS
should
leave
Hardware
Thermal
Control
[
PslApicLoEn
,
PslApicHiEn
]
at
their
default
reset
value
(
D
18
F
3
x
64[7:6] = 00
b
and
should
set
APM
TDP
Control
[
ApmTdpLimitIntEn
] (
D
18
F
4
x
16
C
[4] = 1
b
.
This
workaround
requires
software
to
receive
both
P-state
limit
change
interrupts
and
ApmTdpLimit
change
interrupts
.
Fix
Planned
No
fix
planned
48063
Rev
. 3.18
October
2012
Revision
Guide
for
AMD
Family
15
h
Models
00
h-
0
Fh
Processors
Product
Errata
55