VT8601 Apollo ProMedia
Revision 1.3 September 8, 1999
-136-
Functional Descriptions
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Graphics Controller Power Management
The ProMedia Graphics Controller power mangement feature
set complies with AGP and PCI power management
requirements.
Power Management States
Power management states (D0-D3) for both ACPI and PCI
Bus Power Management (PCI PM) refer to the same states
described in the Device Class PM Reference Specification for
Display Devices, which are equivalent to the VESA™ DPMS
power states. System software should access the ProMedia’s
configuration registers to perform PCI PM state transitions.
Table 12. PCI Power Management States
PCI PM
State
Desktop
Graphics
Notebook
Graphics
State 0
(D0)
DPMS State 0
Fully On
Proprietary State 0
Fully On
State 1
(D1)
DPMS State 1
Standby
(Hsync Off)
Proprietary State 1
Standby
(VCLK Off)
State 2
(D2)
DPMS State 2
Suspend
(Vsync Off)
Proprietary State 2
Suspend
(MCLK/VCLK Both Off)
State 3
(D3)
DPMS State 3
Off
(H/Vsync Both Off)
Same as State 2
Power Management Clock Control
If the system “South Bridge” sends a request to the ProMedia
to power down the memory controller, the ProMedia first uses
CLKRUN# (the same signal appearing external to the
ProMedia) to check to see if the internal graphics controller
needs to access main memory. The graphics controller logic
will detect CLKRUN# high for 2 or 3 PCICLK’s and check if
there are any:
Internal buffers not emptied
PCI Master or AGP Master actions pending
If either condition exists, the graphics controller logic will
assert CLKRUN# low for 2 PCICLK’s to signal the clock
generator to keep PCICLK running.
PME# is not implemented since there are no wake-up
conditions.
Power Management Registers
Power management control for the ProMedia Graphics
Controller is provided by extended registers SR24 (Power
Management Control), GR20 (Standby Timer Control), GR21
(Power Management Control 1), GR22 (Power Management
Control 2), GR23 (Power Status), GR24 (Soft Power Control),
GR25 (Power Control Select), GR26 (DPMS Control), GR27-
28 (GPIO Control), GR2A (Suspend Pin Timer), GR2C
(Miscellaneous Pin Control), GR2F (Miscellaneous Internal
Control), and Graphics Controller PCI Configuration Indices
90-97 (PCI Power Management Registers 1 and 2).
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