On 16/01/2026 15:56, Andrew Lunn wrote:

On Fri, Jan 16, 2026 at 08:09:51PM +0530, sayantan nandy wrote:

quoted

Hi all,

Thanks for the review and comments.

I checked the AN7581 HW and it does support MTU sizes up to 16K. However, as
mentioned by Benjamin, larger packets consume more DMA descriptors, and while
no extra buffers are allocated, this can put pressure on the descriptor rings.

Does the hardware consume DMA descriptors for the full 16K, not just
the number of descriptors needed for the actual received packet size?
That seems like a bad design.

       Andrew

The descriptor buffer size is configurable. The amount of used 
descriptors will be the received packet size % descriptor buffer size + 1.

MvH

Benjamin Larsson