# Errors in dmesg when trying to bring up WiFi using SDIO

**URL:** <https://forums.developer.nvidia.com/t/errors-in-dmesg-when-trying-to-bring-up-wifi-using-sdio/219732>\
**Category:** Jetson Nano\
**Tags:** wifi, board-design\
**Created:** [July 5, 2022, 6:00am UTC](https://forums.developer.nvidia.com/t/errors-in-dmesg-when-trying-to-bring-up-wifi-using-sdio/219732 "2022-07-05T06:00:34Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![surfinride](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@surfinride](https://forums.developer.nvidia.com/u/surfinride)\
**Post date:** [July 15, 2022, 11:47am UTC](https://forums.developer.nvidia.com/t/errors-in-dmesg-when-trying-to-bring-up-wifi-using-sdio/219732/5 "2022-07-15T11:47:07Z")

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Hi Wayne,

Our setup is such that we are powering the WiFi card externally. I found the below in the device tree binding documentation.

```auto
MMC power
---------

Controllers may implement power control from both the connected cards and
the IO signaling (for example to change to high-speed 1.8V signalling). If
the system supports this, then the following two properties should point
to valid regulator nodes:

- vqmmc-supply: supply node for IO line power
- vmmc-supply: supply node for card's power

```

Because the card is powered externally, I changed added the property `nvidia,vmmc-always-on` to the sdhci2 node. But `tegra210-porg-power-tree-p3448-0000-a00.dtsi` sets `vmmc-supply = <&p3448_vdd_3v3_sys>`. Is there a need to put a dummy regulator here because the card is power externally?

I also removed `vqmmc-supply = <&max77620_ldo6>` from an override in `tegra210-porg-plugin-manager.dtsi` and added `vqmcc-supply = <&max77620_sd3>` in the sdhci2 node.

The `max77620_sd3` is 1.8v regulator.

After these changes, the mmc1 logs no longer show the `mmc_rescan_try_freq` go into an endless loop. But I do not see an init message for the WiFi card like you mentioned in you post here: [WiFi bring up on custom carrier board - #12 by WayneWWW](https://forums.developer.nvidia.com/t/wifi-bring-up-on-custom-carrier-board/155198/12)

Loading the driver manually, the mlan0 interface for the WiFi module also isn’t shown.

I am attaching the latest .dtb converted to .dts and the kernel bootlog here.  
[jul15th\_wifi\_on\_sdio\_10.txt](https://forums.developer.nvidia.com/uploads/short-url/14xXOtqT4Sbz2YM6nInVNrghCOK.txt) (56.1 KB)  
[jul15th\_10.dts](https://forums.developer.nvidia.com/uploads/short-url/7lBLtuUKJCdKIKxEntSIakPxWrb.dts) (284.5 KB)

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