SPI driver error when traffic is high

[Cla]

When there is a lot of traffic on the SPI-bus (connected to an SD-card), we see the following error:

`<err> spi_nrfx_spim: Update exceeds current buffer`

Why does it happen? How can we try to avoid it?

Thanks in advance

[Jared]

Hi,

Could you share your code?

The error is from here, which is called from here,

regards

Jared

[Cla]

Thanks for the quick reply. I unfortunately can not share the entire code. I can give some context.

We are using the spi driver to talk to an sd card. We use the sdmmc-subsystem and access it over the disk-access-API.

The disc-access-API is used for different things (the sd-card has a filesystem and a raw partition).

We have cherry picked this fix: https://github.com/zephyrproject-rtos/zephyr/pull/67209 to allow for better sharing of the resource (without the fix, if two threads try to access the sd-card concurrently, one of them would fail).

Do you have any hints as to what that error (spi_nrfx_spim: Update exceeds current buffer) might mean?

If possible, I could try to reduce the code later to something I could share, but it is likely difficult.

[Jared]

Hi,

I can't say that I've seen this error before. Can you set a breakpoint here and share what ctx-tx_len and len is set to when the error happens?

regards

Jared 

[Cla]

I will try.

[Cla]

len=8 and ctx->tx_len=1

[Sigurd Hellesvik]

Hi,

Jared is away a couple of weeks, so I will continue to help with this ticket.

Cla said:

len=8 and ctx->tx_len=1

Are these numbers the same every time or do they vary?

Regards,
Sigurd Hellesvik

[Cla]

I have only seen 8 1