Port 0 Device Sleep (PxDEVSLP0) – Offset 144 - 001 - ID:834576 | Intel® 800 Series Chipset Family Platform Controller Hub (PCH), Volume 2

Intel® 800 Series Chipset Family Platform Controller Hub (PCH), Volume 2

ID	Date	Version	Classification
834576	10/10/2024	001	Public

Port 0 Device Sleep (PxDEVSLP0) – Offset 144

Bit Range	Default	Access	Field Name and Description
31:29	0h	RO	RSVD0 (RSVD0) Reserved
28:25	fh	RW/O	DITO Multiplier (DM) 0's based value that specifies the DITO multiplier that the HBA applies to the specified DITO value, effectively extending the range of DITO from 1ms to 16368ms. A value of 0h indicates a multiplier of 1. A maximum multiplier of 16 may be applied. The HBA computes the total idle timeout as a product of DM and DITO (i.e. DITO actual = DITO *(DM + 1)). These bits are not reset on an HBA reset.
24:15	4h	RW/V	DEVSLP Idle Timeout (DITO) This field specifies the amount of the time (in approximate 1ms granularity) that the HBA shall wait before driving the DEVSLP signal.Hardware reloads its port specific DEVSLP timer with this value each time the port transitions out of DEVSLP state. For example: from DEVSLP to active or PxDEVSLP.ADSE transitions from 0 to a 1. If CAP2.SDS or CAP2.SADM or PxDEVSLP.DSP is cleared to 0 then these bits are read-only 0h and software shall treat these bits as reserved. Software shall only set this value when PxCMD.ST is cleared to 0 and PxDEVSLP.ADSE is cleared to 0. These bits are not reset on an HBA reset.
14:10	ah	RW/V	DEVSLP Minimum Assertion Time (MDAT) This field specifies the minimum amount of time (in 1ms granularity) that the HBA must assert the DEVSLP signal before it may be de-asserted. The nominal value is 10ms and the minimum is 1ms depending on device identification information. If CAP2.SDS is cleared to 0 or PxDEVSLP.DSP is cleared to 0 then these bits are read-only 0h and software shall treat these bits as reserved. Software shall only set this value when PxCMD.ST is cleared to 0, PxDEVSLP.ADSE is cleared to 0, and prior to setting PxCMD.ICC to 8h. These bits are not reset on an HBA reset.
9:2	14h	RW/V	DEVSLP Exit Timeout (DETO) This field specifies the maximum duration (in approximate 1ms granularity) from DEVSLP de-assertion until the device is ready to accept OOB. The nominal value is 20ms while the max value is 255ms depending on device identification information. If CAP2.SDS is cleared to 0 or PxDEVSLP.DSP is cleared to 0 then these bits are read-only 0h and software shall treat these bits as reserved. Software shall only set this value when PxCMD.ST is cleared to 0, PxDEVSLP.ADSE is cleared to 0, and prior to setting PxCMD.ICC to 8h. These bits are not reset on a HBA reset.
1	1h	RW/O	Device Sleep Present (DSP) If set to '1', the platform supports DEVSLP on this port. If cleared to '0', the platform does not support DEVSLP on this port. This bit may only be set to '1' if CAP2.SDS is set to '1'.DSP is mutually exclusive with the PxCMD.HPCP bit and PxCMD.ESP bit. BIOS is required to program this field to 1 if the system supports the DEVSLP feature. Note: These bits are not reset on a HBA reset.
0	0h	RW/V	Aggressive DEVSLP Enable (ADSE) This bit is read/write for HBAs that support aggressive DEVSLP management (CAP2. SADM = 1). When this bit is set to 1, the HBA shall assert the DEVSLP signal after the port has been idle (PxCI = 0h and PxSACT = 0h) for the amount of time specified by the PxDEVSLP.DITO register and the interface is in Slumber (PxSSTS.IPM = 6h). When this bit is cleared to 0, the HBA does not enter DEVSLP unless software directed via PxCMD.ICC. This bit shall only be set to 1 if PxDEVSLP.DSP is set to 1. If this bit is set to 1 and software clears the bit to 0, then the HBA shall de-assert the DEVSLP signal if asserted. These bits are not reset on a HBA reset. BIOS is recommended to program this field to 1 if the platform support the DEVSLP feature. If CAP2.SDS is cleared to 0 or CAP2.SADM is cleared to 0, or if PxDEVSLP.DSP is cleared to 0 then these bits are read-only 0h and software shall treat these bits as reserved.