openwrt/target/linux
Koen Vandeputte a58bcc9e67 ath79: mikrotik: fix beeper phantom noise on RB912
Analysis done by Denis Kalashnikov:

It seems that some ROS versions on some routerboard models have this bug:
after silence boot (no output to uart, no beeps) beeper clicks when wireless traffic is.

https://forum.mikrotik.com/viewtopic.php?f=3&t=92269
https://forum.mikrotik.com/viewtopic.php?t=63399

From these links:

1)
Hello, I have RB951G-2HnD and I noticed strange thing
when I loaded the device with some wireless traffic it
produced strange sound - like hissing, fizzing etc.

2)
Same problem still on 6.33, with silent boot enabled
I hear buzzing noise on wireless load.

3)
The sound is fixed in v5.19, it was a bug that caused beeper to make clicks.

It also got fixed in RouterOS:

* What's new in 5.19 (2012-Jul-16 10:51):
fix ticking sound on RB411UAHL;

* What's new in 6.38.3 (2017-Feb-07 09:52):
rb3011 - fixed noise from buzzer after silent boot;

I've checked with an oscilloscope that:
* When on the ssr beeper pin is 0,
  on the beeper itself is 1 (~5V),
  and when on the ssr beeper pin is 1,
  on the beeper is 0
  The beeper doesn't consume power,
  so 1 should be a default/idle value for the ssr beeper pin).
* When there is wireless traffic (ping packets)
  in the background and the beeper clicks, I see
  pulses on the beeper itself,
  but no pulses on the ssr beeper pin (Q5 pin of 74hc595).
  When I manually toggle the ssr beeper pin I see pulses on both.
  So, it is likely that the phantom beeper clicks are caused by the EMI.

Suggested-by: Denis Kalashnikov <denis281089@gmail.com>
Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
2021-07-01 11:58:36 +02:00
..
apm821xx apm821xx: move CONFIG_REGULATOR to target config 2021-06-13 11:32:49 +02:00
arc770 treewide: do not quote compatible in shell scripts 2021-06-06 19:17:47 +02:00
archs38 treewide: switch the timer frequency to 100 Hz 2021-04-21 10:31:10 +01:00
armvirt treewide: switch the timer frequency to 100 Hz 2021-04-21 10:31:10 +01:00
at91 kernel: move some drm symbols to generic config 2021-06-13 23:30:10 +02:00
ath25 kernel: Activate FORTIFY_SOURCE for MIPS kernel 5.4 2021-04-30 23:51:19 +02:00
ath79 ath79: mikrotik: fix beeper phantom noise on RB912 2021-07-01 11:58:36 +02:00
bcm27xx kernel: bump 5.4 to 5.4.128 2021-06-26 12:49:15 +02:00
bcm47xx bcm47xx: make WGT634U NVRAM patch apply again 2021-03-12 21:09:11 +01:00
bcm53xx kernel: bump 5.4 to 5.4.118 2021-05-23 15:09:06 +02:00
bcm63xx bcm63xx: drop USB LEDs for Technicolor TG582N / ADB P.DG A4001N 2021-06-05 23:39:14 +02:00
bcm4908 bcm4908: fix Ethernet broken state after interface restart 2021-06-22 08:06:13 +02:00
bmips bmips: remove duplicated brcmnand patch 2021-05-17 12:25:34 +02:00
gemini base-files: generate network config with "device" options 2021-05-27 10:58:49 +02:00
generic generic: at803x: mask 1000 Base-X link mode 2021-06-27 13:19:20 +02:00
imx6 imx6: image: drop BOOT_SCRIPT and fix DEVICE_NAME 2021-05-26 14:12:46 +02:00
ipq40xx ipq40xx: add missing case closing symbol 2021-06-28 01:06:08 +02:00
ipq806x ipq806x: fix dedicated cpufreq driver 2021-06-30 23:14:43 +02:00
ipq807x treewide: remove redundant ubifs kconfig symbols 2021-04-21 10:31:07 +01:00
kirkwood treewide: do not quote compatible in shell scripts 2021-06-06 19:17:47 +02:00
lantiq ltq-deu: Mark lantiq DEU broken 2021-06-30 23:14:43 +02:00
layerscape kernel: bump 5.4 to 5.4.128 2021-06-26 12:49:15 +02:00
malta treewide: switch the timer frequency to 100 Hz 2021-04-21 10:31:10 +01:00
mediatek kernel: bump 5.4 to 5.4.126 2021-06-26 12:49:15 +02:00
mpc85xx treewide: switch the timer frequency to 100 Hz 2021-04-21 10:31:10 +01:00
mvebu kernel: bump 5.4 to 5.4.128 2021-06-26 12:49:15 +02:00
mxs treewide: switch the timer frequency to 100 Hz 2021-04-21 10:31:10 +01:00
octeon octeon: use shared function for platform_copy_config() 2021-05-17 01:01:32 +02:00
octeontx kernel: bump 5.4 to 5.4.128 2021-06-26 12:49:15 +02:00
omap kernel: move some drm symbols to generic config 2021-06-13 23:30:10 +02:00
oxnas treewide: remove redundant ubifs kconfig symbols 2021-04-21 10:31:07 +01:00
pistachio treewide: switch the timer frequency to 100 Hz 2021-04-21 10:31:10 +01:00
ramips ramips: add support for Tenbay T-MB5EU-V01 2021-06-27 21:40:27 +02:00
realtek realtek: Fix failsafe mode 2021-06-22 23:23:00 +02:00
rockchip kernel: bump 5.10 to 5.10.43 2021-06-14 01:36:36 +02:00
sunxi linux-firmware: update to version 20210315 and trim down broadcom FW 2021-06-06 00:26:13 +02:00
tegra kernel: move some drm symbols to generic config 2021-06-13 23:30:10 +02:00
uml treewide: switch the timer frequency to 100 Hz 2021-04-21 10:31:10 +01:00
x86 x86: add upgrade support to diag.sh 2021-06-10 10:34:44 +02:00
zynq kernel: move some drm symbols to generic config 2021-06-13 23:30:10 +02:00
Makefile target: use SPDX license identifiers on Makefiles 2021-02-10 15:47:18 +01:00