Visible to Intel only — GUID: owz1481130260782
Ixiasoft
Visible to Intel only — GUID: owz1481130260782
Ixiasoft
17.6.2.5.4. Transmit Polling Suspended
Transmit polling can be suspended by either of the following conditions: †
- The DMA detects a descriptor owned by the Host (TDES0[31]=0). To resume, the driver must give descriptor ownership to the DMA and then issue a Poll Demand command. †
- A frame transmission is aborted when a transmit error because of underflow is detected. The appropriate Transmit Descriptor 0 (TDES0) bit is set. †
If the DMA goes into SUSPEND state because of the first condition, then both Bit 16 (Normal Interrupt Summary) and Bit 2 (Transmit Buffer Unavailable) of Register 5 (Status Register) are set. If the second condition occur, both Bit 15 (Abnormal Interrupt Summary) and Bit 5 (Transmit Underflow) of Register 5 (Status Register) are set, and the information is written to Transmit Descriptor 0, causing the suspension. †
In both cases, the position in the transmit List is retained. The retained position is that of the descriptor following the Last descriptor closed by the DMA. †
The driver must explicitly issue a Transmit Poll Demand command after rectifying the suspension cause. †