sysfs-class-net-cdc_ncm 5.3 KB

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  1. What: /sys/class/net/<iface>/cdc_ncm/min_tx_pkt
  2. Date: May 2014
  3. KernelVersion: 3.16
  4. Contact: Bjørn Mork <bjorn@mork.no>
  5. Description:
  6. The driver will pad NCM Transfer Blocks (NTBs) longer
  7. than this to tx_max, allowing the device to receive
  8. tx_max sized frames with no terminating short
  9. packet. NTBs shorter than this limit are transmitted
  10. as-is, without any padding, and are terminated with a
  11. short USB packet.
  12. Padding to tx_max allows the driver to transmit NTBs
  13. back-to-back without any interleaving short USB
  14. packets. This reduces the number of short packet
  15. interrupts in the device, and represents a tradeoff
  16. between USB bus bandwidth and device DMA optimization.
  17. Set to 0 to pad all frames. Set greater than tx_max to
  18. disable all padding.
  19. What: /sys/class/net/<iface>/cdc_ncm/ndp_to_end
  20. Date: Dec 2015
  21. KernelVersion: 4.5
  22. Contact: Bjørn Mork <bjorn@mork.no>
  23. Description:
  24. Boolean attribute showing the status of the "NDP to
  25. end" quirk. Defaults to 'N', except for devices
  26. already known to need it enabled.
  27. The "NDP to end" quirk makes the driver place the NDP
  28. (the packet index table) after the payload. The NCM
  29. specification does not mandate this, but some devices
  30. are known to be more restrictive. Write 'Y' to this
  31. attribute for temporary testing of a suspect device
  32. failing to work with the default driver settings.
  33. A device entry should be added to the driver if this
  34. quirk is found to be required.
  35. What: /sys/class/net/<iface>/cdc_ncm/rx_max
  36. Date: May 2014
  37. KernelVersion: 3.16
  38. Contact: Bjørn Mork <bjorn@mork.no>
  39. Description:
  40. The maximum NTB size for RX. Cannot exceed the
  41. maximum value supported by the device. Must allow at
  42. least one max sized datagram plus headers.
  43. The actual limits are device dependent. See
  44. dwNtbInMaxSize.
  45. Note: Some devices will silently ignore changes to
  46. this value, resulting in oversized NTBs and
  47. corresponding framing errors.
  48. What: /sys/class/net/<iface>/cdc_ncm/tx_max
  49. Date: May 2014
  50. KernelVersion: 3.16
  51. Contact: Bjørn Mork <bjorn@mork.no>
  52. Description:
  53. The maximum NTB size for TX. Cannot exceed the
  54. maximum value supported by the device. Must allow at
  55. least one max sized datagram plus headers.
  56. The actual limits are device dependent. See
  57. dwNtbOutMaxSize.
  58. What: /sys/class/net/<iface>/cdc_ncm/tx_timer_usecs
  59. Date: May 2014
  60. KernelVersion: 3.16
  61. Contact: Bjørn Mork <bjorn@mork.no>
  62. Description:
  63. Datagram aggregation timeout in µs. The driver will
  64. wait up to 3 times this timeout for more datagrams to
  65. aggregate before transmitting an NTB frame.
  66. Valid range: 5 to 4000000
  67. Set to 0 to disable aggregation.
  68. The following read-only attributes all represent fields of the
  69. structure defined in section 6.2.1 "GetNtbParameters" of "Universal
  70. Serial Bus Communications Class Subclass Specifications for Network
  71. Control Model Devices" (CDC NCM), Revision 1.0 (Errata 1), November
  72. 24, 2010 from USB Implementers Forum, Inc. The descriptions are
  73. quoted from table 6-3 of CDC NCM: "NTB Parameter Structure".
  74. What: /sys/class/net/<iface>/cdc_ncm/bmNtbFormatsSupported
  75. Date: May 2014
  76. KernelVersion: 3.16
  77. Contact: Bjørn Mork <bjorn@mork.no>
  78. Description:
  79. - Bit 0: 16-bit NTB supported (set to 1)
  80. - Bit 1: 32-bit NTB supported
  81. - Bits 2 – 15: reserved (reset to zero; must be ignored by host)
  82. What: /sys/class/net/<iface>/cdc_ncm/dwNtbInMaxSize
  83. Date: May 2014
  84. KernelVersion: 3.16
  85. Contact: Bjørn Mork <bjorn@mork.no>
  86. Description:
  87. IN NTB Maximum Size in bytes
  88. What: /sys/class/net/<iface>/cdc_ncm/wNdpInDivisor
  89. Date: May 2014
  90. KernelVersion: 3.16
  91. Contact: Bjørn Mork <bjorn@mork.no>
  92. Description:
  93. Divisor used for IN NTB Datagram payload alignment
  94. What: /sys/class/net/<iface>/cdc_ncm/wNdpInPayloadRemainder
  95. Date: May 2014
  96. KernelVersion: 3.16
  97. Contact: Bjørn Mork <bjorn@mork.no>
  98. Description:
  99. Remainder used to align input datagram payload within
  100. the NTB: (Payload Offset) mod (wNdpInDivisor) =
  101. wNdpInPayloadRemainder
  102. What: /sys/class/net/<iface>/cdc_ncm/wNdpInAlignment
  103. Date: May 2014
  104. KernelVersion: 3.16
  105. Contact: Bjørn Mork <bjorn@mork.no>
  106. Description:
  107. NDP alignment modulus for NTBs on the IN pipe. Shall
  108. be a power of 2, and shall be at least 4.
  109. What: /sys/class/net/<iface>/cdc_ncm/dwNtbOutMaxSize
  110. Date: May 2014
  111. KernelVersion: 3.16
  112. Contact: Bjørn Mork <bjorn@mork.no>
  113. Description:
  114. OUT NTB Maximum Size
  115. What: /sys/class/net/<iface>/cdc_ncm/wNdpOutDivisor
  116. Date: May 2014
  117. KernelVersion: 3.16
  118. Contact: Bjørn Mork <bjorn@mork.no>
  119. Description:
  120. OUT NTB Datagram alignment modulus
  121. What: /sys/class/net/<iface>/cdc_ncm/wNdpOutPayloadRemainder
  122. Date: May 2014
  123. KernelVersion: 3.16
  124. Contact: Bjørn Mork <bjorn@mork.no>
  125. Description:
  126. Remainder used to align output datagram payload
  127. offsets within the NTB: Padding, shall be transmitted
  128. as zero by function, and ignored by host. (Payload
  129. Offset) mod (wNdpOutDivisor) = wNdpOutPayloadRemainder
  130. What: /sys/class/net/<iface>/cdc_ncm/wNdpOutAlignment
  131. Date: May 2014
  132. KernelVersion: 3.16
  133. Contact: Bjørn Mork <bjorn@mork.no>
  134. Description:
  135. NDP alignment modulus for use in NTBs on the OUT
  136. pipe. Shall be a power of 2, and shall be at least 4.
  137. What: /sys/class/net/<iface>/cdc_ncm/wNtbOutMaxDatagrams
  138. Date: May 2014
  139. KernelVersion: 3.16
  140. Contact: Bjørn Mork <bjorn@mork.no>
  141. Description:
  142. Maximum number of datagrams that the host may pack
  143. into a single OUT NTB. Zero means that the device
  144. imposes no limit.