SPRADS6 March   2026 AM68A , AM69A , TDA4VM

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Data Movement within the TDA4VH
    1. 1.1 Common Bus Architecture Subsystem (CBASS)
    2. 1.2 Navigator Subsystems (NAVSS)
      1. 1.2.1 NAVSS North Bridge (NB)
    3. 1.3 Multicore Shared Memory Controller (MSMC)
  5. 2Quality of Service (QoS)
    1. 2.1 NAVSS0
      1. 2.1.1 NAVSS0 North Bridge
        1. 2.1.1.1 Normal vs Real-Time Traffic
    2. 2.2 Multicore Shared Memory Controller (MSMC)
    3. 2.3 DDR Subsystem (DDRSS)
      1. 2.3.1 MSMC2DDR Bridge
      2. 2.3.2 Class of Service (CoS)
    4. 2.4 QoS Summary
  6. 3Case Study: Display Sync Lost Issue
    1. 3.1 Problem Statement
    2. 3.2 Setup and Recreation
      1. 3.2.1 Requirements
        1. 3.2.1.1 RTOS Patches
          1. 3.2.1.1.1 0001-vision_apps-Remove-the-DSS-application-from-MCU2_0.patch
          2. 3.2.1.1.2 0002-vision_apps-Remove-display-use-from-the-AVP-demo.patch
        2. 3.2.1.2 Linux Patches
          1. 3.2.1.2.1 0001-arm64-dts-ti-k3-j784s4-vision-apps-Re-enable-DSS-for.patch
      2. 3.2.2 Host Setup
      3. 3.2.3 Target Setup
      4. 3.2.4 Recreation
    3. 3.3 Debugging QoS
      1. 3.3.1 CPTracer
        1. 3.3.1.1  Setup
        2. 3.3.1.2  Profiling Throughput
        3. 3.3.1.3  Profiling Latency
        4. 3.3.1.4  Profiling Transactions
        5. 3.3.1.5  Profiling Relevant Routes
        6. 3.3.1.6  Profiling DSS Throughput
          1. 3.3.1.6.1 Theoretical DSS Throughput
          2. 3.3.1.6.2 Normal DSS Throughput
          3. 3.3.1.6.3 DSS Throughput with the AVP Demo Running
        7. 3.3.1.7  Profiling DSS Latency
        8. 3.3.1.8  Profiling C7x Throughput
        9. 3.3.1.9  Profiling C7x Throughput vs DSS Latency
        10. 3.3.1.10 Profiling C7x_4 Core Transactions
      2. 3.3.2 Editing QoS Settings
        1. 3.3.2.1 Editing Order ID
          1. 3.3.2.1.1 DSS Order ID
          2. 3.3.2.1.2 C7x Order ID
        2. 3.3.2.2 NRT and RT Routing
          1. 3.3.2.2.1 NRT and RT Routing in U-Boot
        3. 3.3.2.3 Editing Priority
          1. 3.3.2.3.1 DSS Priority
          2. 3.3.2.3.2 C7x Priority
      3. 3.3.3 Editing CoS Mappings
        1. 3.3.3.1 CoS Mapping Registers
        2. 3.3.3.2 Checking CoS Mappings
    4. 3.4 Fixing the DSS Sync Losts
      1. 3.4.1 Remap C7x_4 Core Transactions
        1. 3.4.1.1 ti-u-boot-2023.04
        2. 3.4.1.2 ti-u-boot-2025.01
      2. 3.4.2 Honor All Priorities
        1. 3.4.2.1 ti-u-boot-2023.04
        2. 3.4.2.2 ti-u-boot-2025.01
  7. 4Summary
  8. 5References
3.3.1.6.3 DSS Throughput with the AVP Demo Running

The following image displays the throughput of DSS transactions with the AVP demo running.

AVP Demo DSS ThroughputFigure 3-6 AVP Demo DSS Throughput.

Table 3-5 Measured DSS Throughput with AVP Demo
DSS Throughput of 1 EMIFCorrected Throughput for 4 EMIFs
Bytes per Frame825753633030144
Bits per Byte8
fps30
Number of EMIFs Measured14
Bits per Frame66060288264241152
Mib per Frame63252
Data Rate (bps)19818086407927234560
Data Rate (Mibps)1890

7560

The total throughput falls short of what is required to display 3840x2160@30fps. This is what causes the sync losts. Only 264241152 bits were sent in a frame instead of 265420800 bits.