| Message ID | 1401101625-12342-9-git-send-email-bjorn@mork.no |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
Bjørn Mork wrote: > +++ b/Documentation/ABI/testing/sysfs-class-net-cdc_ncm > @@ -0,0 +1,143 @@ > +What: /sys/class/net/<iface>/cdc_ncm/min_tx_pkt > +Date: May 2014 > +KernelVersion: 3.16 > +Contact: Bjørn Mork <bjorn@mork.no> > +Description: > + The driver will pad frames longer than this to tx_max, ^^^^^^ longer or shorter? > +What: /sys/class/net/<iface>/cdc_ncm/rx_max > +Date: May 2014 > +KernelVersion: 3.16 > +Contact: Bjørn Mork <bjorn@mork.no> > +Description: > + The maximum NCM Transfer Block (NTB) size for RX. > + Cannot exceed the maximum value supported by the > + device. Must allow at least one max sized datagram > + plus headers. > + > + The actual limits are device dependent. See > + dwNtbInMaxSize. > + > + Note: Some devices will silently ignore changes to > + this value, resulting in oversized NTBs and > + corresponding framing errors. That behavior makes the setting only so-so useful. Could the driver know which devices do this, or is it inconsistent even across individual devices which are otherwise indistinguishable? > +What: /sys/class/net/<iface>/cdc_ncm/tx_timer_usecs > +Date: May 2014 > +KernelVersion: 3.16 > +Contact: Bjørn Mork <bjorn@mork.no> > +Description: > + Datagram aggregation timeout in µs. The driver will > + wait up to 3 times this timeout for more datagrams to > + aggregate before transmitting a NTB frame. ^ "an NTB frame" might be better since N sounds like "enn". > + > + Valid range: 5 to 4000000 > + > + Set to 0 to disable aggregation. > + > +The following read only attributes all represent fields of the read-only? //Peter -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Peter Stuge <peter@stuge.se> writes: > Bjørn Mork wrote: >> +++ b/Documentation/ABI/testing/sysfs-class-net-cdc_ncm >> @@ -0,0 +1,143 @@ >> +What: /sys/class/net/<iface>/cdc_ncm/min_tx_pkt >> +Date: May 2014 >> +KernelVersion: 3.16 >> +Contact: Bjørn Mork <bjorn@mork.no> >> +Description: >> + The driver will pad frames longer than this to tx_max, > ^^^^^^ > longer or shorter? longer. If it is shorter then it is sent as-is. I guess this setting could use a bit more explanation here. > >> +What: /sys/class/net/<iface>/cdc_ncm/rx_max >> +Date: May 2014 >> +KernelVersion: 3.16 >> +Contact: Bjørn Mork <bjorn@mork.no> >> +Description: >> + The maximum NCM Transfer Block (NTB) size for RX. >> + Cannot exceed the maximum value supported by the >> + device. Must allow at least one max sized datagram >> + plus headers. >> + >> + The actual limits are device dependent. See >> + dwNtbInMaxSize. >> + >> + Note: Some devices will silently ignore changes to >> + this value, resulting in oversized NTBs and >> + corresponding framing errors. > > That behavior makes the setting only so-so useful. Could the driver > know which devices do this, or is it inconsistent even across > individual devices which are otherwise indistinguishable? I have no idea, and I don't know how to find out. I've observed the failure on one of my MBIM modems. That's all I know. I believe the setting still is useful for all spec compliant devices, and even most of the others. The firmware bug does make it difficult to do any automagic tuning. But it's not impossible. The tuning application can do a bit of probing and looking at the frame error counter. >> +What: /sys/class/net/<iface>/cdc_ncm/tx_timer_usecs >> +Date: May 2014 >> +KernelVersion: 3.16 >> +Contact: Bjørn Mork <bjorn@mork.no> >> +Description: >> + Datagram aggregation timeout in µs. The driver will >> + wait up to 3 times this timeout for more datagrams to >> + aggregate before transmitting a NTB frame. > ^ > "an NTB frame" might be better since N sounds like "enn". OK >> + >> + Valid range: 5 to 4000000 >> + >> + Set to 0 to disable aggregation. >> + >> +The following read only attributes all represent fields of the > > read-only? OK Thanks for reviewing this. Bjørn -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/ABI/testing/sysfs-class-net-cdc_ncm b/Documentation/ABI/testing/sysfs-class-net-cdc_ncm new file mode 100644 index 000000000000..971c13297f06 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-net-cdc_ncm @@ -0,0 +1,143 @@ +What: /sys/class/net/<iface>/cdc_ncm/min_tx_pkt +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + The driver will pad frames longer than this to tx_max, + allowing the device to receive tx_max sized frames + with no terminating short packet. This represents a + tradeoff between USB bus bandwidth and device DMA + optimization. + + Set to 0 to pad all frames. Set greater than tx_max to + disable all padding. + +What: /sys/class/net/<iface>/cdc_ncm/rx_max +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + The maximum NCM Transfer Block (NTB) size for RX. + Cannot exceed the maximum value supported by the + device. Must allow at least one max sized datagram + plus headers. + + The actual limits are device dependent. See + dwNtbInMaxSize. + + Note: Some devices will silently ignore changes to + this value, resulting in oversized NTBs and + corresponding framing errors. + +What: /sys/class/net/<iface>/cdc_ncm/tx_max +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + The maximum NTB size for TX. Cannot exceed the + maximum value supported by the device. Must allow at + least one max sized datagram plus headers. + + The actual limits are device dependent. See + dwNtbOutMaxSize. + +What: /sys/class/net/<iface>/cdc_ncm/tx_timer_usecs +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + Datagram aggregation timeout in µs. The driver will + wait up to 3 times this timeout for more datagrams to + aggregate before transmitting a NTB frame. + + Valid range: 5 to 4000000 + + Set to 0 to disable aggregation. + +The following read only attributes all represent fields of the +structure defined in section 6.2.1 "GetNtbParameters" of "Universal +Serial Bus Communications Class Subclass Specifications for Network +Control Model Devices" (CDC NCM), Revision 1.0 (Errata 1), November +24, 2010 from USB Implementers Forum, Inc. The descriptions are +quoted from table 6-3 of CDC NCM: "NTB Parameter Structure". + +What: /sys/class/net/<iface>/cdc_ncm/bmNtbFormatsSupported +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + Bit 0: 16-bit NTB supported (set to 1) + Bit 1: 32-bit NTB supported + Bits 2 – 15: reserved (reset to zero; must be ignored by host) + +What: /sys/class/net/<iface>/cdc_ncm/dwNtbInMaxSize +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + IN NTB Maximum Size in bytes + +What: /sys/class/net/<iface>/cdc_ncm/wNdpInDivisor +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + Divisor used for IN NTB Datagram payload alignment + +What: /sys/class/net/<iface>/cdc_ncm/wNdpInPayloadRemainder +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + Remainder used to align input datagram payload within + the NTB: (Payload Offset) mod (wNdpInDivisor) = + wNdpInPayloadRemainder + +What: /sys/class/net/<iface>/cdc_ncm/wNdpInAlignment +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + NDP alignment modulus for NTBs on the IN pipe. Shall + be a power of 2, and shall be at least 4. + +What: /sys/class/net/<iface>/cdc_ncm/dwNtbOutMaxSize +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + OUT NTB Maximum Size + +What: /sys/class/net/<iface>/cdc_ncm/wNdpOutDivisor +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + OUT NTB Datagram alignment modulus + +What: /sys/class/net/<iface>/cdc_ncm/wNdpOutPayloadRemainder +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + Remainder used to align output datagram payload + offsets within the NTB: Padding, shall be transmitted + as zero by function, and ignored by host. (Payload + Offset) mod (wNdpOutDivisor) = wNdpOutPayloadRemainder + +What: /sys/class/net/<iface>/cdc_ncm/wNdpOutAlignment +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + NDP alignment modulus for use in NTBs on the OUT + pipe. Shall be a power of 2, and shall be at least 4. + +What: /sys/class/net/<iface>/cdc_ncm/wNtbOutMaxDatagrams +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + Maximum number of datagrams that the host may pack + into a single OUT NTB. Zero means that the device + imposes no limit.
Adding documentation for all the driver specific sysfs attributes. Signed-off-by: Bjørn Mork <bjorn@mork.no> --- Documentation/ABI/testing/sysfs-class-net-cdc_ncm | 143 ++++++++++++++++++++++ 1 file changed, 143 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-net-cdc_ncm