[PATCH] net/intel: improve Rx descriptor ring size checks

[Bruce Richardson]

On Mon, Dec 15, 2025 at 05:58:33PM +0000, Bruce Richardson wrote:
> On Mon, Dec 15, 2025 at 06:54:50PM +0100, Morten Brørup wrote:
> > > From: Bruce Richardson [mailto:bruce.richardson at intel.com]
> > > Sent: Monday, 15 December 2025 18.36
> > > 
> > > The default Rx ring size checks did not account for the fact that the
> > > port would not work correctly if the Rx ring size was only twice the
> > > free threshold size or less, so add in a new check for this. This would
> > > generally only apply in cases where very small rings sizes are being
> > > used, for example, with default Rx free thresh of 32, only ring size of
> > > 64 would cause issues.
> > > 
> > > Signed-off-by: Bruce Richardson <bruce.richardson at intel.com>
> > > ---
> > 
> > Does dev_info.rx_desc_lim.nb_min returned by rte_eth_dev_info_get() need correction too?
> > 
> The minimum number of descriptors stays the same, however, if choosing the
> minimum number of descriptors you may need to reduce the rx_free_thresh
> value.
> 
However, I think you raise a good point. I'll see about adding a specific
error message in case the user is using the default threshold and setting
the min ring size.

/Bruce