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1What: /sys/class/net/<iface>/cdc_ncm/min_tx_pkt2Date: May 20143KernelVersion: 3.164Contact: Bjørn Mork <bjorn@mork.no>5Description:6 The driver will pad NCM Transfer Blocks (NTBs) longer7 than this to tx_max, allowing the device to receive8 tx_max sized frames with no terminating short9 packet. NTBs shorter than this limit are transmitted10 as-is, without any padding, and are terminated with a11 short USB packet.12 13 Padding to tx_max allows the driver to transmit NTBs14 back-to-back without any interleaving short USB15 packets. This reduces the number of short packet16 interrupts in the device, and represents a tradeoff17 between USB bus bandwidth and device DMA optimization.18 19 Set to 0 to pad all frames. Set greater than tx_max to20 disable all padding.21 22What: /sys/class/net/<iface>/cdc_ncm/ndp_to_end23Date: Dec 201524KernelVersion: 4.525Contact: Bjørn Mork <bjorn@mork.no>26Description:27 Boolean attribute showing the status of the "NDP to28 end" quirk. Defaults to 'N', except for devices29 already known to need it enabled.30 31 The "NDP to end" quirk makes the driver place the NDP32 (the packet index table) after the payload. The NCM33 specification does not mandate this, but some devices34 are known to be more restrictive. Write 'Y' to this35 attribute for temporary testing of a suspect device36 failing to work with the default driver settings.37 38 A device entry should be added to the driver if this39 quirk is found to be required.40 41What: /sys/class/net/<iface>/cdc_ncm/rx_max42Date: May 201443KernelVersion: 3.1644Contact: Bjørn Mork <bjorn@mork.no>45Description:46 The maximum NTB size for RX. Cannot exceed the47 maximum value supported by the device. Must allow at48 least one max sized datagram plus headers.49 50 The actual limits are device dependent. See51 dwNtbInMaxSize.52 53 Note: Some devices will silently ignore changes to54 this value, resulting in oversized NTBs and55 corresponding framing errors.56 57What: /sys/class/net/<iface>/cdc_ncm/tx_max58Date: May 201459KernelVersion: 3.1660Contact: Bjørn Mork <bjorn@mork.no>61Description:62 The maximum NTB size for TX. Cannot exceed the63 maximum value supported by the device. Must allow at64 least one max sized datagram plus headers.65 66 The actual limits are device dependent. See67 dwNtbOutMaxSize.68 69What: /sys/class/net/<iface>/cdc_ncm/tx_timer_usecs70Date: May 201471KernelVersion: 3.1672Contact: Bjørn Mork <bjorn@mork.no>73Description:74 Datagram aggregation timeout in µs. The driver will75 wait up to 3 times this timeout for more datagrams to76 aggregate before transmitting an NTB frame.77 78 Valid range: 5 to 400000079 80 Set to 0 to disable aggregation.81 82The following read-only attributes all represent fields of the83structure defined in section 6.2.1 "GetNtbParameters" of "Universal84Serial Bus Communications Class Subclass Specifications for Network85Control Model Devices" (CDC NCM), Revision 1.0 (Errata 1), November8624, 2010 from USB Implementers Forum, Inc. The descriptions are87quoted from table 6-3 of CDC NCM: "NTB Parameter Structure".88 89What: /sys/class/net/<iface>/cdc_ncm/bmNtbFormatsSupported90Date: May 201491KernelVersion: 3.1692Contact: Bjørn Mork <bjorn@mork.no>93Description:94 - Bit 0: 16-bit NTB supported (set to 1)95 - Bit 1: 32-bit NTB supported96 - Bits 2 – 15: reserved (reset to zero; must be ignored by host)97 98What: /sys/class/net/<iface>/cdc_ncm/dwNtbInMaxSize99Date: May 2014100KernelVersion: 3.16101Contact: Bjørn Mork <bjorn@mork.no>102Description:103 IN NTB Maximum Size in bytes104 105What: /sys/class/net/<iface>/cdc_ncm/wNdpInDivisor106Date: May 2014107KernelVersion: 3.16108Contact: Bjørn Mork <bjorn@mork.no>109Description:110 Divisor used for IN NTB Datagram payload alignment111 112What: /sys/class/net/<iface>/cdc_ncm/wNdpInPayloadRemainder113Date: May 2014114KernelVersion: 3.16115Contact: Bjørn Mork <bjorn@mork.no>116Description:117 Remainder used to align input datagram payload within118 the NTB: (Payload Offset) mod (wNdpInDivisor) =119 wNdpInPayloadRemainder120 121What: /sys/class/net/<iface>/cdc_ncm/wNdpInAlignment122Date: May 2014123KernelVersion: 3.16124Contact: Bjørn Mork <bjorn@mork.no>125Description:126 NDP alignment modulus for NTBs on the IN pipe. Shall127 be a power of 2, and shall be at least 4.128 129What: /sys/class/net/<iface>/cdc_ncm/dwNtbOutMaxSize130Date: May 2014131KernelVersion: 3.16132Contact: Bjørn Mork <bjorn@mork.no>133Description:134 OUT NTB Maximum Size135 136What: /sys/class/net/<iface>/cdc_ncm/wNdpOutDivisor137Date: May 2014138KernelVersion: 3.16139Contact: Bjørn Mork <bjorn@mork.no>140Description:141 OUT NTB Datagram alignment modulus142 143What: /sys/class/net/<iface>/cdc_ncm/wNdpOutPayloadRemainder144Date: May 2014145KernelVersion: 3.16146Contact: Bjørn Mork <bjorn@mork.no>147Description:148 Remainder used to align output datagram payload149 offsets within the NTB: Padding, shall be transmitted150 as zero by function, and ignored by host. (Payload151 Offset) mod (wNdpOutDivisor) = wNdpOutPayloadRemainder152 153What: /sys/class/net/<iface>/cdc_ncm/wNdpOutAlignment154Date: May 2014155KernelVersion: 3.16156Contact: Bjørn Mork <bjorn@mork.no>157Description:158 NDP alignment modulus for use in NTBs on the OUT159 pipe. Shall be a power of 2, and shall be at least 4.160 161What: /sys/class/net/<iface>/cdc_ncm/wNtbOutMaxDatagrams162Date: May 2014163KernelVersion: 3.16164Contact: Bjørn Mork <bjorn@mork.no>165Description:166 Maximum number of datagrams that the host may pack167 into a single OUT NTB. Zero means that the device168 imposes no limit.169