Intel® 80219 General Purpose PCI Processor
6.The MTTR1 (Core
Problem: | The MTTR1 (Core |
| internal bus request signal (REQ#). All agents on the bus, except the core, maintain their assertion |
| on REQ# signals upon receiving a retry. When the MCU is busy this means that the core must wait |
| for other agents to complete their transactions before the core gains access to memory. Due to the |
| fact that internal bus agents initiate larger transactions than the core, this issue results in an |
| unbalanced access to the internal bus biased to these other agents (DMA, ATU, etc.). When opera- |
| tional, the MTTR1 is intended to correct this balance. See Section 11.2.2 of the Intel® 80219 |
| General Purpose PCI Processor Developer’s Manual for more information on the MTTR1 |
| function. |
Implication: | In the case of the MCU internal bus target, this problem is compounded by the many internal bus |
| retries that are issued by the MCU when under heavily loaded conditions. The result is that the |
| internal bus arbiter removes the core access to the bus when the core deasserts REQ#. This |
| condition may result in the core being locked out of accessing the MCU until other internal bus |
| agents have completed their transaction(s) (i.e., when the DMA is in the process of a large block |
| transfer of data, the core may have to wait until the DMA transaction is completed before it would |
| have access to the internal bus to initiate its transaction). |
Workaround: | No workaround. |
Status: | NoFix. |
7.The MCU supports a page size of 2 Kbytes for 64-bit mode
Problem: | The Intel® 80219 General Purpose PCI Processor Developer’s Manual (Section 6.1.1 and Section |
| 6.2.2.3) states that the MCU supports a page size of 4 Kbytes for |
| |
Implication: | The MCU supports a page size of 2 Kbytes for |
Workaround: | No workaround. |
Status: | NoFix. |
22 | Specification Update |