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xaptum / xaptum-buildroot

External Buildroot tree for Xaptum hardware
GNU General Public License v2.0
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mmc1 fails to switch signaling voltage #118

Closed drbild closed 4 years ago

drbild commented 5 years ago

The following errors appears in the router card boot logs.

mmc1: Switching to 3.3V signalling voltage failed
sdhci-at91 b0000000.sdio-host: could not set regulator OCR (-22)

I believe that our board only supports the 1.8V voltage for mmc1, so it can't switch to 3.3V. This should be ok.

Our device tree should indicate that the voltage controller is fixed as 1.8V. Not sure if this message is because our device tree is missing that config, or if the log message is just informing us that a fixed 1.8V regulator can't be switched to 3.3V.

drbild commented 4 years ago

After inspecting our device tree again, I think the latter is happening. We've told it that the regulator only supports 1.8V, but the mmc driver still tries to switch to 3.3V and logs an error. That's a kernel issue, not our issue, so closing this.