OpenWrt/LEDE Project

  • Status Unconfirmed
  • Percent Complete
    0%
  • Task Type Bug Report
  • Category Kernel
  • Assigned To No-one
  • Operating System All
  • Severity Medium
  • Priority Very Low
  • Reported Version openwrt-19.07
  • Due in Version Undecided
  • Due Date Undecided
  • Private
Attached to Project: OpenWrt/LEDE Project
Opened by Thomas Beckler - 09.05.2020

FS#3080 - ramips/mt7621 Netgear R6220 WIFI 5 GHz issue

I am using a Netgear R6220 router. My router has one “bad erase block”

[    2.859177] Scanning device for bad blocks
[    2.952205] Bad eraseblock 361 at 0x000002d20000
[    3.116833] 6 fixed-partitions partitions found on MTD device MT7621-NAND

Every test is done with default settings. For me it is easier to debug this issue with openwrt in station mode, but it applies to AccessPoint/Master as well.

  • 2.4 GHz WIFI operation as expected
  • 5 GHz WIFI only affected
  • low throughput only in openwrt TX direction / openwrt RX direction OK
  • things got much worse with openwrt 19.07.02 → openwrt 18.06.08 was better
    This is why I suspect that it is related to FS#1926 - MTD partition offset not correctly mapped when bad eraseblocks present.
    This fix has been integrated in 19.07. I don’t want to revert this change, as this is the first version openwrt sets the correct MAC address.

Comarison of OpenWrt 18.06.08 and 19.07.02

  • OpenWrt 18.06.08: TX Power is set to 3dBm
  • OpenWrt 19.07.02: TX Power is set to 20dBm (default?)
  • In both cases/logs The “HT Mode is VHT80”
  • Changing the TX Power in 19.07.02 has no effect
    Resource is busy

My guess/conclusion is that

  • the calibration data is not taken into account (maybe it was never and openwrt 18.06 was just lucky)
  • The offset to read the calibration data has changed with openwrt 19.07.02. This is why things got worse (for me)

Attached is the mtd4.bin (factory). I don’t know if this helps for this issue.

OpenWrt 18.06.08

WIFI 5 GHz operation “normal”. Means I can use any channel in 5 GHz and get good performance/throughput.
Channel 36
TX ~80Mbit/s
RX ~95Mbit/s
Channel 124
TX ~80Mbit/s
RX ~95Mbit/s

iw --debug phy phy1 info
phy phy1
        max # scan SSIDs: 4
        max scan IEs length: 2247 bytes
        max # sched scan SSIDs: 0
        max # match sets: 0
        max # scan plans: 1
        max scan plan interval: -1
        max scan plan iterations: 0
        Retry short limit: 7
        Retry long limit: 4
        Coverage class: 0 (up to 0m)
        Available Antennas: TX 0x3 RX 0x3
        Configured Antennas: TX 0x3 RX 0x3
        Supported interface modes:
                 * IBSS
                 * managed
                 * AP
                 * AP/VLAN
                 * monitor
                 * mesh point
        Band 2:
                Capabilities: 0x1ff
                        RX LDPC
                        HT20/HT40
                        SM Power Save disabled
                        RX Greenfield
                        RX HT20 SGI
                        RX HT40 SGI
                        TX STBC
                        RX STBC 1-stream
                        Max AMSDU length: 3839 bytes
                        No DSSS/CCK HT40
                Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
                Minimum RX AMPDU time spacing: 4 usec (0x05)
                HT TX/RX MCS rate indexes supported: 0-15
                VHT Capabilities (0x018001b0):
                        Max MPDU length: 3895
                        Supported Channel Width: neither 160 nor 80+80
                        RX LDPC
                        short GI (80 MHz)
                        TX STBC
                VHT RX MCS set:
                        1 streams: MCS 0-9
                        2 streams: MCS 0-9
                        3 streams: not supported
                        4 streams: not supported
                        5 streams: not supported
                        6 streams: not supported
                        7 streams: not supported
                        8 streams: not supported
                VHT RX highest supported: 0 Mbps
                VHT TX MCS set:
                        1 streams: MCS 0-9
                        2 streams: MCS 0-9
                        3 streams: not supported
                        4 streams: not supported
                        5 streams: not supported
                        6 streams: not supported
                        7 streams: not supported
                        8 streams: not supported
                VHT TX highest supported: 0 Mbps
                Frequencies:
                        * 5180 MHz [36] (3.0 dBm)
                        * 5200 MHz [40] (3.0 dBm)
                        * 5220 MHz [44] (3.0 dBm)
                        * 5240 MHz [48] (3.0 dBm)
                        * 5260 MHz [52] (3.0 dBm) (no IR, radar detection)
                        * 5280 MHz [56] (3.0 dBm) (no IR, radar detection)
                        * 5300 MHz [60] (3.0 dBm) (no IR, radar detection)
                        * 5320 MHz [64] (3.0 dBm) (no IR, radar detection)
                        * 5500 MHz [100] (3.0 dBm) (no IR, radar detection)
                        * 5520 MHz [104] (3.0 dBm) (no IR, radar detection)
                        * 5540 MHz [108] (3.0 dBm) (no IR, radar detection)
                        * 5560 MHz [112] (3.0 dBm) (no IR, radar detection)
                        * 5580 MHz [116] (3.0 dBm) (no IR, radar detection)
                        * 5600 MHz [120] (3.0 dBm) (no IR, radar detection)
                        * 5620 MHz [124] (3.0 dBm) (no IR, radar detection)
                        * 5640 MHz [128] (3.0 dBm) (no IR, radar detection)
                        * 5660 MHz [132] (3.0 dBm) (no IR, radar detection)
                        * 5680 MHz [136] (3.0 dBm) (no IR, radar detection)
                        * 5700 MHz [140] (3.0 dBm) (no IR, radar detection)
                        * 5745 MHz [149] (3.0 dBm) (no IR)
                        * 5765 MHz [153] (3.0 dBm) (no IR)
                        * 5785 MHz [157] (3.0 dBm) (no IR)
                        * 5805 MHz [161] (3.0 dBm) (no IR)
                        * 5825 MHz [165] (3.0 dBm) (no IR)
        valid interface combinations:
                 * #{ IBSS } <= 1, #{ managed, AP, mesh point } <= 8,
                   total <= 8, #channels <= 1, STA/AP BI must match, radar detect widths: { 20 MHz (no HT), 20 MHz, 40 MHz, 80 MHz }

        HT Capability overrides:
                 * MCS: ff ff ff ff ff ff ff ff ff ff
                 * maximum A-MSDU length
                 * supported channel width
                 * short GI for 40 MHz
                 * max A-MPDU length exponent
                 * min MPDU start spacing
        Device supports VHT-IBSS.
root@OpenWrt:~# iw --debug wlan1 info
Interface wlan1
        ifindex 8
        wdev 0x100000002
        addr xx:xx:xx:xx:xx:xx
        ssid Africa_5GHz
        type managed
        wiphy 1
        channel 124 (5620 MHz), width: 80 MHz, center1: 5610 MHz
        txpower 3.00 dBm
wifi status
"radio1": {
                "up": true,
                "pending": false,
                "autostart": true,
                "disabled": false,
                "retry_setup_failed": false,
                "config": {
                        "hwmode": "11a",
                        "path": "pci0000:00\/0000:00:00.0\/0000:01:00.0",
                        **"htmode": "VHT80",**
                        "channel": "124",
                        "country": "00",
                        "legacy_rates": true,
                        "disabled": false

OpenWrt 19.07.02

Channel 36
TX ~1.25 Mbit/s
RX ~95 Mbit/s
Channel 124
TX ~1.25 Mbit/s
RX ~95 Mbit/s

root@OpenWrt:~# iw --debug phy1 info
Wiphy phy1
        max # scan SSIDs: 4
        max scan IEs length: 2247 bytes
        max # sched scan SSIDs: 0
        max # match sets: 0
        max # scan plans: 1
        max scan plan interval: -1
        max scan plan iterations: 0
        Retry short limit: 7
        Retry long limit: 4
        Coverage class: 0 (up to 0m)
        Available Antennas: TX 0x3 RX 0x3
        Configured Antennas: TX 0x3 RX 0x3
        Supported interface modes:
                 * IBSS
                 * managed
                 * AP
                 * AP/VLAN
                 * monitor
                 * mesh point
        Band 2:
                Capabilities: 0x1ff
                        RX LDPC
                        HT20/HT40
                        SM Power Save disabled
                        RX Greenfield
                        RX HT20 SGI
                        RX HT40 SGI
                        TX STBC
                        RX STBC 1-stream
                        Max AMSDU length: 3839 bytes
                        No DSSS/CCK HT40
                Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
                Minimum RX AMPDU time spacing: 4 usec (0x05)
                HT TX/RX MCS rate indexes supported: 0-15
                VHT Capabilities (0x318001b0):
                        Max MPDU length: 3895
                        Supported Channel Width: neither 160 nor 80+80
                        RX LDPC
                        short GI (80 MHz)
                        TX STBC
                        RX antenna pattern consistency
                        TX antenna pattern consistency
                VHT RX MCS set:
                        1 streams: MCS 0-9
                        2 streams: MCS 0-9
                        3 streams: not supported
                        4 streams: not supported
                        5 streams: not supported
                        6 streams: not supported
                        7 streams: not supported
                        8 streams: not supported
                VHT RX highest supported: 0 Mbps
                VHT TX MCS set:
                        1 streams: MCS 0-9
                        2 streams: MCS 0-9
                        3 streams: not supported
                        4 streams: not supported
                        5 streams: not supported
                        6 streams: not supported
                        7 streams: not supported
                        8 streams: not supported
                VHT TX highest supported: 0 Mbps
                Frequencies:
                        * 5180 MHz [36] (20.0 dBm)
                        * 5200 MHz [40] (20.0 dBm)
                        * 5220 MHz [44] (20.0 dBm)
                        * 5240 MHz [48] (20.0 dBm)
                        * 5260 MHz [52] (20.0 dBm) (no IR, radar detection)
                        * 5280 MHz [56] (20.0 dBm) (no IR, radar detection)
                        * 5300 MHz [60] (20.0 dBm) (no IR, radar detection)
                        * 5320 MHz [64] (20.0 dBm) (no IR, radar detection)
                        * 5500 MHz [100] (20.0 dBm) (no IR, radar detection)
                        * 5520 MHz [104] (20.0 dBm) (no IR, radar detection)
                        * 5540 MHz [108] (20.0 dBm) (no IR, radar detection)
                        * 5560 MHz [112] (20.0 dBm) (no IR, radar detection)
                        * 5580 MHz [116] (20.0 dBm) (no IR, radar detection)
                        * 5600 MHz [120] (20.0 dBm) (no IR, radar detection)
                        * 5620 MHz [124] (20.0 dBm) (no IR, radar detection)
                        * 5640 MHz [128] (20.0 dBm) (no IR, radar detection)
                        * 5660 MHz [132] (20.0 dBm) (no IR, radar detection)
                        * 5680 MHz [136] (20.0 dBm) (no IR, radar detection)
                        * 5700 MHz [140] (20.0 dBm) (no IR, radar detection)
                        * 5745 MHz [149] (20.0 dBm) (no IR)
                        * 5765 MHz [153] (20.0 dBm) (no IR)
                        * 5785 MHz [157] (20.0 dBm) (no IR)
                        * 5805 MHz [161] (20.0 dBm) (no IR)
                        * 5825 MHz [165] (20.0 dBm) (no IR)
        valid interface combinations:
                 * #{ IBSS } <= 1, #{ managed, AP, mesh point } <= 8,
                   total <= 8, #channels <= 1, STA/AP BI must match, radar detect widths: { 20 MHz (no HT), 20 MHz, 40 MHz, 80 MHz }

        HT Capability overrides:
                 * MCS: ff ff ff ff ff ff ff ff ff ff
                 * maximum A-MSDU length
                 * supported channel width
                 * short GI for 40 MHz
                 * max A-MPDU length exponent
                 * min MPDU start spacing
        Supported extended features:
                * [ VHT_IBSS ]: VHT-IBSS
                * [ RRM ]: RRM
                * [ CQM_RSSI_LIST ]: multiple CQM_RSSI_THOLD records
                * [ CONTROL_PORT_OVER_NL80211 ]: control port over nl80211
                * [ TXQS ]: FQ-CoDel-enabled intermediate TXQs
root@OpenWrt:~# iw --debug wlan1 info
Interface wlan1
        ifindex 9
        wdev 0x100000003
        addr xx:xx:xx:xx:xx:xx
        ssid Africa_5GHz
        type managed
        wiphy 1
        channel 124 (5620 MHz), width: 80 MHz, center1: 5610 MHz
        txpower 20.00 dBm
        multicast TXQ:
                qsz-byt qsz-pkt flows   drops   marks   overlmt hashcol tx-bytestx-packets
                0       0       0       0       0       0       0       0      0
wifi status
"radio1": {
                "up": false,
                "pending": false,
                "autostart": false,
                "disabled": false,
                "retry_setup_failed": false,
                "config": {
                        "hwmode": "11a",
                        "path": "pci0000:00/0000:00:00.0/0000:01:00.0",
                        "htmode": "VHT80",
                        "channel": "124",
                        "country": "00",
                        "legacy_rates": false
Thomas Beckler commented on 09.05.2020 14:40

going back to my own compilation based on openwrt 18.06.01
→ 5 GHz WIFI has never worked well but it was not as bad as with 19.07.02. I have several backups of the flash. Can someone help me to

  • adjust the read offset for the calibration data?
  • understand how i find the correct offset?

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