Re: [PATCH v22 net-next 02/12] net/nebula-matrix: add core driver architecture and HW layer initialization

[Jakub Kicinski]

On Thu, 23 Jul 2026 12:00:54 +0800 illusion.wang wrote:
> +	err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
> +	if (err) {
> +		dev_dbg(dev, "Configure DMA 64 bit mask failed, err = %d\n",
> +			err);
> +		dma_32_err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
> +		if (dma_32_err) {

Read the documentation for the DMA API, dma_set_mask_and_coherent()
is guaranteed to succeed in some cases..