[OpenWrt-Devel] Broken WiFi on QCA9533 rev. 2

[David Bauer]

Hello Adrian,

On 11/5/19 5:14 PM, Adrian Schmutzler wrote:
> Hi David,
> 
> thanks for your response.
> 
> To me it looks like qca953x already uses 25 MHz clock, or am I looking at the wrong value:

Yes, however ath9k does not use this value but tries to determine the reference clock
based on the bootstrap bit (see first link in my previous E-Mail), so the value
from the device tree is never used for ath9k.

Best wishes
David

> 
> https://github.com/openwrt/openwrt/blob/master/target/linux/ath79/dts/qca953x.dtsi#L27
> 
> Best
> 
> Adrian
> 
> 
> On 5 November 2019 16:46:59 CET, David Bauer <mail at david-bauer.net> wrote:
> 
>     Hello Adrian,
> 
>     during the CPE210v2 bringup it was discovered that the CPE210 has the wrong bootstrap option set
>     for it's 25 MHz reference clock. Because of this, the device was originally not even booting with ar71xx.
> 
>     On ath79, the reference clock is not detected based on the bootstrap option, but set by the DTS.
>     The twist however is the ath9k driver, whose OF patch still reads this register. [0]
> 
>     On ar71xx, the platform data was always set to true for the QCA9533 [1]
> 
>     So you can try to force the settings for 25MHz reference clock for all QCA953x regardless of the bootstrap
>     settings to keep the behavior in line with ar71xx.
> 
>     I have no device to verify this, however it's a good candidate for the root cause. ;)
> 
>     [0] https://github.com/openwrt/openwrt/blob/master/package/kernel/mac80211/patches/ath/552-ahb_of.patch#L237
>     [1] https://github.com/openwrt/openwrt/blob/master/target/linux/ar71xx/patches-4.14/620-MIPS-ath79-add-support-for-QCA953x-SoC.patch#L260
> 
>     Best wishes
>     David
> 
>     On 11/5/19 3:05 PM, Adrian Schmutzler wrote:
> 
>         Hi,
> 
>         for quite some time already we are struggling with broken WiFi on some TP-Link CPE devices having QCA9533 rev. 2 (QCA9533-BL3A SOC) in common.
> 
>         I'd be happy on some help here, since I've exhausted my debugging capabilities.
> 
> 
>         1. Symptoms: WiFi looks up on the device, some TX traffic is shown in ifconfig, RX is zero. The AP cannot be found by clients. "iw dev wlan0 scan" returns nothing.
> 
>         2. Affected devices: TP-Link CPE210 v2/v3, CPE220 v3 (all QCA9533 rev. 2?); no other QCA9533 devices known to be affected (specific to CPE or to QCA9533 rev. 2?)
> 
>         3. For a certain model, there are devices which are working correctly and others which don't. There is no known indicator to find out whether a device works or not. The state of a device does not change as far as we know (always working or never working).
> 
>         4. So far, only 2.4 GHZ-only devices were affected
> 
>         5. There is no diagnostic output that indicates a WiFi problem. dmesg/logread look normal, there is no difference when compared between working and not-working devices (despite RX=0/scan as stated above)
> 
>         6. The problem seems to be present from the beginning (device support patches), it just has been overlooked since it's not occurring on every device.
> 
>         7. The ar71xx firmware for all devices works flawlessly, so it is an ath79-specific problem.
> 
> 
>         Other findings that might be connected or not:
> 
>         a. On ath79 phy0 uses irq=11/irq=12 and on ar71xx irq=47. eth0 uses irq=4 on both targets.
> 
>         b. The following gpio is only found on ar71xx: gpio-495 ( |ath9k-phy0 ) in lo
> 
> 
>         I currently own a CPE210v2 with the bug and can test suggestions (if I'm capable of implementing them).
>         There is a device support PR for the CPE220 v3 suffering from the same problem: https://github.com/openwrt/openwrt/pull/2514
> 
>         Despite, further reading may be found in forum discussion and bug report:
>         https://bugs.openwrt.org/index.php?do=details&task_id=2333
>         https://bugs.openwrt.org/index.php?do=details&task_id=2478
>         https://forum.openwrt.org/t/ath79-tp-link-cpe210-v2-0-wifi-not-working/40666
> 
>         Initial support for CPE210 v2/v3 was done by me and bluelineXY, both already involved in the discussion. ;-)
> 
>         Thanks for any hints!
> 
>         Adrian
>         ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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> 
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