From: Stephen Hemminger <stephen@networkplumber.org>
To: Jan Petrous <jan.petrous@nxp.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: napi driver for multiport device with the only one dma channel - is it possible?
Date: Thu, 13 Dec 2018 10:18:32 -0800 [thread overview]
Message-ID: <20181213101832.00352dc2@xeon-e3> (raw)
In-Reply-To: <6357c3732fba381aca915608e744571fcfbb2359.camel@nxp.com>
On Thu, 13 Dec 2018 13:30:50 +0000
Jan Petrous <jan.petrous@nxp.com> wrote:
> Hi,
>
> am I understand it right that I can not use NAPI-powered design in case
> when there is only one rx queue and one tx queue (only two
> dma channels) usable for data transfer with the ethernet controller for
> all interfaces (2 ports or more)?
>
> I could imagine there would be possibility to declare for example rx
> queue sharable between napi interfaces, but I was not able to find
> anything like that.
>
> I agree that it is a bit strange configuration but we have to support
> such corner case (when other dma channels are used by independent
> systems).
>
> I seems like I have to create two drivers - one with napi, when at
> least the same number of dma channels are free for use and second one
> without napi (because of not enough dma channels).
>
>
> Thanks.
> /Jan
It is possible. Sky2 for some hardware has a single NAPI (on port 0)
and if the card is dual port the napi of port 0 is used by port 1.
next prev parent reply other threads:[~2018-12-13 18:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-13 13:30 napi driver for multiport device with the only one dma channel - is it possible? Jan Petrous
2018-12-13 18:18 ` Stephen Hemminger [this message]
2018-12-14 8:09 ` Jan Petrous
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