1 What: /sys/class/net/<iface>/cdc_ncm 1 What: /sys/class/net/<iface>/cdc_ncm/min_tx_pkt
2 Date: May 2014 2 Date: May 2014
3 KernelVersion: 3.16 3 KernelVersion: 3.16
4 Contact: Bjørn Mork <bjorn@mork.no> 4 Contact: Bjørn Mork <bjorn@mork.no>
5 Description: 5 Description:
6 The driver will pad NCM Transf 6 The driver will pad NCM Transfer Blocks (NTBs) longer
7 than this to tx_max, allowing 7 than this to tx_max, allowing the device to receive
8 tx_max sized frames with no te 8 tx_max sized frames with no terminating short
9 packet. NTBs shorter than this 9 packet. NTBs shorter than this limit are transmitted
10 as-is, without any padding, an 10 as-is, without any padding, and are terminated with a
11 short USB packet. 11 short USB packet.
12 12
13 Padding to tx_max allows the d 13 Padding to tx_max allows the driver to transmit NTBs
14 back-to-back without any inter 14 back-to-back without any interleaving short USB
15 packets. This reduces the num 15 packets. This reduces the number of short packet
16 interrupts in the device, and 16 interrupts in the device, and represents a tradeoff
17 between USB bus bandwidth and 17 between USB bus bandwidth and device DMA optimization.
18 18
19 Set to 0 to pad all frames. Se 19 Set to 0 to pad all frames. Set greater than tx_max to
20 disable all padding. 20 disable all padding.
21 21
22 What: /sys/class/net/<iface>/cdc_ncm 22 What: /sys/class/net/<iface>/cdc_ncm/ndp_to_end
23 Date: Dec 2015 23 Date: Dec 2015
24 KernelVersion: 4.5 24 KernelVersion: 4.5
25 Contact: Bjørn Mork <bjorn@mork.no> 25 Contact: Bjørn Mork <bjorn@mork.no>
26 Description: 26 Description:
27 Boolean attribute showing the 27 Boolean attribute showing the status of the "NDP to
28 end" quirk. Defaults to 'N', 28 end" quirk. Defaults to 'N', except for devices
29 already known to need it enabl 29 already known to need it enabled.
30 30
31 The "NDP to end" quirk makes t 31 The "NDP to end" quirk makes the driver place the NDP
32 (the packet index table) after 32 (the packet index table) after the payload. The NCM
33 specification does not mandate 33 specification does not mandate this, but some devices
34 are known to be more restricti 34 are known to be more restrictive. Write 'Y' to this
35 attribute for temporary testin 35 attribute for temporary testing of a suspect device
36 failing to work with the defau 36 failing to work with the default driver settings.
37 37
38 A device entry should be added 38 A device entry should be added to the driver if this
39 quirk is found to be required. 39 quirk is found to be required.
40 40
41 What: /sys/class/net/<iface>/cdc_ncm 41 What: /sys/class/net/<iface>/cdc_ncm/rx_max
42 Date: May 2014 42 Date: May 2014
43 KernelVersion: 3.16 43 KernelVersion: 3.16
44 Contact: Bjørn Mork <bjorn@mork.no> 44 Contact: Bjørn Mork <bjorn@mork.no>
45 Description: 45 Description:
46 The maximum NTB size for RX. 46 The maximum NTB size for RX. Cannot exceed the
47 maximum value supported by the 47 maximum value supported by the device. Must allow at
48 least one max sized datagram p 48 least one max sized datagram plus headers.
49 49
50 The actual limits are device d 50 The actual limits are device dependent. See
51 dwNtbInMaxSize. 51 dwNtbInMaxSize.
52 52
53 Note: Some devices will silent 53 Note: Some devices will silently ignore changes to
54 this value, resulting in overs 54 this value, resulting in oversized NTBs and
55 corresponding framing errors. 55 corresponding framing errors.
56 56
57 What: /sys/class/net/<iface>/cdc_ncm 57 What: /sys/class/net/<iface>/cdc_ncm/tx_max
58 Date: May 2014 58 Date: May 2014
59 KernelVersion: 3.16 59 KernelVersion: 3.16
60 Contact: Bjørn Mork <bjorn@mork.no> 60 Contact: Bjørn Mork <bjorn@mork.no>
61 Description: 61 Description:
62 The maximum NTB size for TX. 62 The maximum NTB size for TX. Cannot exceed the
63 maximum value supported by the 63 maximum value supported by the device. Must allow at
64 least one max sized datagram p 64 least one max sized datagram plus headers.
65 65
66 The actual limits are device d 66 The actual limits are device dependent. See
67 dwNtbOutMaxSize. 67 dwNtbOutMaxSize.
68 68
69 What: /sys/class/net/<iface>/cdc_ncm 69 What: /sys/class/net/<iface>/cdc_ncm/tx_timer_usecs
70 Date: May 2014 70 Date: May 2014
71 KernelVersion: 3.16 71 KernelVersion: 3.16
72 Contact: Bjørn Mork <bjorn@mork.no> 72 Contact: Bjørn Mork <bjorn@mork.no>
73 Description: 73 Description:
74 Datagram aggregation timeout i 74 Datagram aggregation timeout in µs. The driver will
75 wait up to 3 times this timeou 75 wait up to 3 times this timeout for more datagrams to
76 aggregate before transmitting 76 aggregate before transmitting an NTB frame.
77 77
78 Valid range: 5 to 4000000 78 Valid range: 5 to 4000000
79 79
80 Set to 0 to disable aggregatio 80 Set to 0 to disable aggregation.
81 81
82 The following read-only attributes all represe 82 The following read-only attributes all represent fields of the
83 structure defined in section 6.2.1 "GetNtbPara 83 structure defined in section 6.2.1 "GetNtbParameters" of "Universal
84 Serial Bus Communications Class Subclass Speci 84 Serial Bus Communications Class Subclass Specifications for Network
85 Control Model Devices" (CDC NCM), Revision 1.0 85 Control Model Devices" (CDC NCM), Revision 1.0 (Errata 1), November
86 24, 2010 from USB Implementers Forum, Inc. Th 86 24, 2010 from USB Implementers Forum, Inc. The descriptions are
87 quoted from table 6-3 of CDC NCM: "NTB Paramet 87 quoted from table 6-3 of CDC NCM: "NTB Parameter Structure".
88 88
89 What: /sys/class/net/<iface>/cdc_ncm 89 What: /sys/class/net/<iface>/cdc_ncm/bmNtbFormatsSupported
90 Date: May 2014 90 Date: May 2014
91 KernelVersion: 3.16 91 KernelVersion: 3.16
92 Contact: Bjørn Mork <bjorn@mork.no> 92 Contact: Bjørn Mork <bjorn@mork.no>
93 Description: 93 Description:
94 - Bit 0: 16-bit NTB supported 94 - Bit 0: 16-bit NTB supported (set to 1)
95 - Bit 1: 32-bit NTB supported 95 - Bit 1: 32-bit NTB supported
96 - Bits 2 – 15: reserved (res 96 - Bits 2 – 15: reserved (reset to zero; must be ignored by host)
97 97
98 What: /sys/class/net/<iface>/cdc_ncm 98 What: /sys/class/net/<iface>/cdc_ncm/dwNtbInMaxSize
99 Date: May 2014 99 Date: May 2014
100 KernelVersion: 3.16 100 KernelVersion: 3.16
101 Contact: Bjørn Mork <bjorn@mork.no> 101 Contact: Bjørn Mork <bjorn@mork.no>
102 Description: 102 Description:
103 IN NTB Maximum Size in bytes 103 IN NTB Maximum Size in bytes
104 104
105 What: /sys/class/net/<iface>/cdc_ncm 105 What: /sys/class/net/<iface>/cdc_ncm/wNdpInDivisor
106 Date: May 2014 106 Date: May 2014
107 KernelVersion: 3.16 107 KernelVersion: 3.16
108 Contact: Bjørn Mork <bjorn@mork.no> 108 Contact: Bjørn Mork <bjorn@mork.no>
109 Description: 109 Description:
110 Divisor used for IN NTB Datagr 110 Divisor used for IN NTB Datagram payload alignment
111 111
112 What: /sys/class/net/<iface>/cdc_ncm 112 What: /sys/class/net/<iface>/cdc_ncm/wNdpInPayloadRemainder
113 Date: May 2014 113 Date: May 2014
114 KernelVersion: 3.16 114 KernelVersion: 3.16
115 Contact: Bjørn Mork <bjorn@mork.no> 115 Contact: Bjørn Mork <bjorn@mork.no>
116 Description: 116 Description:
117 Remainder used to align input 117 Remainder used to align input datagram payload within
118 the NTB: (Payload Offset) mod 118 the NTB: (Payload Offset) mod (wNdpInDivisor) =
119 wNdpInPayloadRemainder 119 wNdpInPayloadRemainder
120 120
121 What: /sys/class/net/<iface>/cdc_ncm 121 What: /sys/class/net/<iface>/cdc_ncm/wNdpInAlignment
122 Date: May 2014 122 Date: May 2014
123 KernelVersion: 3.16 123 KernelVersion: 3.16
124 Contact: Bjørn Mork <bjorn@mork.no> 124 Contact: Bjørn Mork <bjorn@mork.no>
125 Description: 125 Description:
126 NDP alignment modulus for NTBs 126 NDP alignment modulus for NTBs on the IN pipe. Shall
127 be a power of 2, and shall be 127 be a power of 2, and shall be at least 4.
128 128
129 What: /sys/class/net/<iface>/cdc_ncm 129 What: /sys/class/net/<iface>/cdc_ncm/dwNtbOutMaxSize
130 Date: May 2014 130 Date: May 2014
131 KernelVersion: 3.16 131 KernelVersion: 3.16
132 Contact: Bjørn Mork <bjorn@mork.no> 132 Contact: Bjørn Mork <bjorn@mork.no>
133 Description: 133 Description:
134 OUT NTB Maximum Size 134 OUT NTB Maximum Size
135 135
136 What: /sys/class/net/<iface>/cdc_ncm 136 What: /sys/class/net/<iface>/cdc_ncm/wNdpOutDivisor
137 Date: May 2014 137 Date: May 2014
138 KernelVersion: 3.16 138 KernelVersion: 3.16
139 Contact: Bjørn Mork <bjorn@mork.no> 139 Contact: Bjørn Mork <bjorn@mork.no>
140 Description: 140 Description:
141 OUT NTB Datagram alignment mod 141 OUT NTB Datagram alignment modulus
142 142
143 What: /sys/class/net/<iface>/cdc_ncm 143 What: /sys/class/net/<iface>/cdc_ncm/wNdpOutPayloadRemainder
144 Date: May 2014 144 Date: May 2014
145 KernelVersion: 3.16 145 KernelVersion: 3.16
146 Contact: Bjørn Mork <bjorn@mork.no> 146 Contact: Bjørn Mork <bjorn@mork.no>
147 Description: 147 Description:
148 Remainder used to align output 148 Remainder used to align output datagram payload
149 offsets within the NTB: Paddin 149 offsets within the NTB: Padding, shall be transmitted
150 as zero by function, and ignor 150 as zero by function, and ignored by host. (Payload
151 Offset) mod (wNdpOutDivisor) = 151 Offset) mod (wNdpOutDivisor) = wNdpOutPayloadRemainder
152 152
153 What: /sys/class/net/<iface>/cdc_ncm 153 What: /sys/class/net/<iface>/cdc_ncm/wNdpOutAlignment
154 Date: May 2014 154 Date: May 2014
155 KernelVersion: 3.16 155 KernelVersion: 3.16
156 Contact: Bjørn Mork <bjorn@mork.no> 156 Contact: Bjørn Mork <bjorn@mork.no>
157 Description: 157 Description:
158 NDP alignment modulus for use 158 NDP alignment modulus for use in NTBs on the OUT
159 pipe. Shall be a power of 2, a 159 pipe. Shall be a power of 2, and shall be at least 4.
160 160
161 What: /sys/class/net/<iface>/cdc_ncm 161 What: /sys/class/net/<iface>/cdc_ncm/wNtbOutMaxDatagrams
162 Date: May 2014 162 Date: May 2014
163 KernelVersion: 3.16 163 KernelVersion: 3.16
164 Contact: Bjørn Mork <bjorn@mork.no> 164 Contact: Bjørn Mork <bjorn@mork.no>
165 Description: 165 Description:
166 Maximum number of datagrams th 166 Maximum number of datagrams that the host may pack
167 into a single OUT NTB. Zero me 167 into a single OUT NTB. Zero means that the device
168 imposes no limit. 168 imposes no limit.
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