Linus Walleij writes: > On Tue, Feb 22, 2022 at 1:19 AM Alvin Šipraga wrote: >> > On Mon, Feb 21, 2022 at 7:46 PM Alvin Šipraga wrote: > >> > What I worry about is whether we need to do a similar patch to >> > rtl8366rb_phy_read() and rtl8366rb_phy_write() in >> > rtl8366rb.c? >> >> Unfortunately I do not have the hardware to test rtl8366rb.c, so I can >> only speculate. But I gave some hints in the commit message which might >> help in checking whether or not it is an issue on that hardware as >> well. The code for rtl8366rb_phy_read() looks similar, but since this is >> a quirk of the hardware design, it could be that it is not >> necessary. The only way is to test. > > I can test it. Great! I have attached a test patch to insert these stray register accesses inside the PHY read/write functions: 0001-TEST-net-dsa-realtek-rtl8366rb-provoke-stray-reg-acc.patch Set the module parameter stray_access to 1 in order to enable stray register access. I did this in case you don't build it as a module but still want to do A/B testing - just remove it if I goofed. > >> If you or somebody else can confirm that it is an issue for RTL8366RB as >> well, I will happily send a patch to the list for testing. You can for >> example try spamming PHY register reads with phytool while also reading >> off switch registers via regmap debugfs. See also the discussion in [1]. >> >> [1] https://lore.kernel.org/netdev/878rukib4f.fsf@bang-olufsen.dk/ > > If you have time to write a patch I'd love testing it! Attached also a patch with a proposed fix - if indeed it is an issue - along the same lines as the second patch in this series. You'll also need the first patch from this series (attached for convenience): 0001-net-dsa-realtek-allow-subdrivers-to-externally-lock-.patch 0002-TEST-net-dsa-realtek-rtl8366rb-serialize-indirect-PH.patch All patches are against net-next and build-tested only, so you might want to double check if the results are unexpected. Kind regards, Alvin > > Yours, > Linus Walleij