Specifications

3.2.2 Integrated Graphics VBIOS and SBIOS Interfaces
Existing interfaces between the SBIOS and VBIOS, and between the display driver
and VBIOS are used for the integrated graphics controller.
3.2.3 Discrete Graphics VBIOS and SBIOS Interfaces
Discrete graphics VBIOS and SBIOS interfaces for PX5.0 are the same as in PX4.0.
Please refer to the Muxless ATI Switchable Graphics PX4.0 Functional Specification
for
Intel platforms and AMD Platform Switchable Graphics and Dual Graphics Design
Guidance and Functional Specification, revision 1.5, for AMD platforms.
Note: On designs where BACO functionality is required, BACO has to be enabled in
the dGPU
video BIOS.
3.2.4 SBIOS Requirements
The SBIOS has to turn ON both the dGPU and fGPU/iGPU during boot-up and resume
from S3 or S4.
3.2.4.1 ATPX Functions
ATPX ControlMethod functions that control the dGPU power and reset are
implemented in the SBIOS. These functions will be invoked by the display driver.
The following functions are critical on a switchable graphics design:
• Function 0 (Verify Interface):
• Required for any switchable graphics design.
• Function 1 (Get AMD PowerXpress™ Parameters):
• Bits 0 to 6 and 11 to 31 must be set to 0.
• Bit 7 indicates that a dynamic scheme is supported, if it is set to 1.
• Bit 9 indicates that a fixed scheme is not supported, if it is set to 1.
• Bit 10 indicates that a full dGPU power off in a dynamic scheme is
supported, if it is set to 1.
• Function 2 (Power Control):
• Required for the fixed scheme.
• Required for dGPU power off under the dynamic scheme.
Please refer to
Switchable Graphics ACPI Control Methods, revision 0.26, for the
SBIOS ATPX function description on Intel platforms, and PowerXpress ACPI Control
Methods, revision 0.26A, for the SBIOS ATPX function description on AMD platforms.
Interfaces and Requirements 17
© 2011 Advanced Micro Devices, Inc.
Proprietary and Confidential - Do not duplicate.
Muxless Switchable Graphics Technology PX5.0 Functional Specification
137-41940-10