[LEDE-DEV] [PATCH] linux/arc*: disable MAC frame filter in DW GMAC

[Daniel Golle]

Hi Alexey,

On Tue, Aug 16, 2016 at 06:06:20AM +0000, Alexey Brodkin wrote:
> Hi Felix,
> 
> On Wed, 2016-07-27 at 17:19 +0200, Felix Fietkau wrote:
> > On 2016-07-27 14:11, Alexey Brodkin wrote:
> > > 
> > > For some [still unknown] reason in ARC SDP boards
> > > DW GMAC doesn't enter promiscuous mode if eth0 gets
> > > added to the br-lan interface before Ethernet PHY finishes
> > > autonegotiation (PHY gets reset on DW GMAC start).
> >
> > I think this is something we need to look at more closely instead of
> > just papering over it in this way. By the way, arc* aren't the only ones
> > using stmmac, ipq806x uses it as well and might be equally affected.
> > Did you check if the network stack tells the driver to go into promisc
> > mode? Or does the frame filtering registers simply get clobbered
> > somewhere internally?
> >
> > Let's do some more testing and get this fixed properly...
> 
> So I spent quite some time with that, short summary could be found here:
> http://lists.infradead.org/pipermail/linux-snps-arc/2016-August/001395.html
> 
> Probably most important summary for us here is:
> ------------------------->8--------------------------
> Unfortunately I cannot figure out why GMAC behaves that way.
> As per GMAC's databook the only reason for it to not react on a register
> being written is missing input clock but there's no reason for the
> clock to be missing and I don't seem to have a way to check if there's
> a problem with clock or not.
> ------------------------->8--------------------------
> 
> It worth trying on other boards with DW GMAC but the only other board
> except ARC SDP ones is Cubieboard2 with sunxi-gmac (which is a kind of
> DW GMAC as I may see from its Linux's driver) but on CB2 all works as
> exected. If somebody wants to volunteer I'll be more than happy to work
> with him/her trying to get more datapoints.

stmac/dwmac works as expected on Oxford/PLXTECH OX82x/NAS782x (oxnas
target on OpenWrt/LEDE) as well.


> 
> And I do think in the meantime it's good to apply this patch so people
> get working Wireless AP without extra patching of sources or what's even
> better with snapshot images.
> 
> -Alexey
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