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Intel® 945G/945GZ/945GC/ 945P/945PL Express Chipset Family ...

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Host-PCI <strong>Express</strong>* Bridge Registers (D1:F0) (<strong>Intel®</strong> 82<strong>945G</strong>/82<strong>945G</strong>C/82<strong>945P</strong>/82<strong>945P</strong>L Only)<br />

5.1.53 VC1RCTL—VC1 Resource Control (D1:F0)<br />

PCI Device: 1<br />

Address Offset: 120–123h<br />

Default Value: 01000000h<br />

Access: RO, R/W<br />

Size: 32 bits<br />

This register controls the resources associated with PCI <strong>Express</strong> Virtual Channel 1.<br />

Bit Access &<br />

Default<br />

31 R/W<br />

0b<br />

30:27 Reserved<br />

26:24 R/W<br />

001b<br />

23:8 Reserved<br />

7:1 R/W<br />

00h<br />

0 RO<br />

0b<br />

Description<br />

VC1 Enable: Software must use the VC Negotiation Pending bit to check whether<br />

the VC negotiation is complete. When VC Negotiation Pending bit is cleared, a 1<br />

read from this VC Enable bit indicates that the VC is enabled (Flow Control<br />

Initialization is completed for the PCI <strong>Express</strong>* port); a 0 read from this bit<br />

indicates that the Virtual Channel is currently disabled.<br />

0 = Virtual Channel is disabled.<br />

1 = Virtual Channel is enabled. See exceptions in following notes.<br />

NOTES:<br />

1. To enable a Virtual Channel, the VC Enable bits for that Virtual<br />

Channel must be set in both components on a Link.<br />

2. To disable a Virtual Channel, the VC Enable bits for that Virtual<br />

Channel must be cleared in both components on a Link.<br />

3. Software must ensure that no traffic is using a Virtual Channel at the<br />

time it is disabled.<br />

4. Software must fully disable a Virtual Channel in both components on a<br />

Link before re-enabling the Virtual Channel.<br />

BIOS Requirement: This field must not be set to 1b.<br />

VC1 ID: This field assigns a VC ID to the VC resource. The assigned value must<br />

be non-zero. This field cannot be modified when the VC is already enabled.<br />

TC/VC1 Map: This field indicates the TCs (Traffic Classes) that are mapped to<br />

the VC resource. Bit locations within this field correspond to TC values. For<br />

example, when bit 7 is set in this field, TC7 is mapped to this VC resource. When<br />

more than one bit in this field is set, it indicates that multiple TCs are mapped to<br />

the VC resource. To remove one or more TCs from the TC/VC map of an enabled<br />

VC, software must ensure that no new or outstanding transactions with the TC<br />

labels are targeted at the given Link.<br />

TC0/VC1 Map: Traffic Class 0 is always routed to VC0.<br />

Intel ® 82<strong>945G</strong>/82<strong>945G</strong>/82<strong>945G</strong>C GMCH and 82<strong>945P</strong>/82<strong>945P</strong>L MCH Datasheet 151

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