Messages in this thread | | | Date | Thu, 18 Aug 2022 17:05:53 +0200 | From | Michael Walle <> | Subject | Re: [PATCH devicetree 0/3] NXP LS1028A DT changes for multiple switch CPU ports |
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Am 2022-08-18 16:55, schrieb Vladimir Oltean: > On Thu, Aug 18, 2022 at 04:49:49PM +0200, Michael Walle wrote: >> Is it used automatically or does the userspace has to configure >> something? > > DSA doesn't yet support multiple CPU ports, but even when it will, the > second DSA master still won't be used automatically. If you want more > details about the proposed UAPI to use the second CPU port, see here: > https://patchwork.kernel.org/project/netdevbpf/cover/20220523104256.3556016-1-olteanv@gmail.com/ > >> > Care has been taken that this change does not produce regressions when >> > using updated device trees with old kernels that do not support multiple >> > DSA CPU ports. The only difference for old kernels will be the >> > appearance of a new net device (for &enetc_port3) which will not be very >> > useful for much of anything. >> >> Mh, I don't understand. Does it now cause regressions or not? I mean >> besides that there is a new unused interface? > > It didn't cause regressions until kernel 5.13 when commit adb3dccf090b > ("net: dsa: felix: convert to the new .change_tag_protocol DSA API") > happened, then commit 00fa91bc9cc2 ("net: dsa: felix: fix tagging > protocol changes with multiple CPU ports") fixed that regression and > was > backported to the linux-5.15.y stable branch AFAIR. So at least kernels > 5.15 and newer should work properly with the new device trees.
Thanks for the details!
>> I was just thinking of that systemready stuff where the u-boot might >> supply its (newer) device tree to an older kernel, i.e. an older >> debian >> or similar. >> >> -michael > > Yeah, I hear you, I'm doing my best to make the driver work with a > one-size-fits-all device tree, both ways around.
TBH I don't really care much, I was merely curious what to expect.
-michael
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