> -----Original Message----- > From: Francois Romieu [mailto:rom...@fr.zoreil.com] > Sent: Thursday, May 12, 2016 10:09 PM > To: Ard Biesheuvel <ard.biesheu...@linaro.org> > Cc: David Miller <da...@davemloft.net>; netdev@vger.kernel.org; Ricardo > Salveti <ricardo.salv...@linaro.org>; Leo Duran <leo.du...@amd.com>; G > Gregory <graeme.greg...@linaro.org>; nic_swsd <nic_s...@realtek.com>; > Hau <h...@realtek.com> > Subject: Re: [PATCH] r8169: default to 64-bit DMA on systems without memory > below 4 GB > > > On 12 May 2016 at 01:58, David Miller <da...@davemloft.net> wrote: > > > From: Ard Biesheuvel <ard.biesheu...@linaro.org> > > > Date: Wed, 11 May 2016 09:47:49 +0200 > [...] > > > I think we should just seriously consider changing the default, it's > > > a really outdated reasoning behind the current default setting. > > > Maybe relevant a decade ago, but probably not now. > > > > > > And if the card is completely disfunctional in said configuration, > > > the default is definitely wrong. > > > > The card is indeed completely disfunctional. So we could try to > > resurrect 353176888386 ("r8169: enable 64-bit DMA by default for PCI > > Express devices"), and instead of backing it out again if regressions > > are reported, blacklist the particular chips. This is a much better > > approach, since then we can also print some kind of diagnostic on > > those arm64 systems why such a blacklisted NIC is not supported. > > I doubt there will be much *reporting* from broken systems that include plain > old PCI realtek chipsets (r8169.c::RTL_CFG_0). Changing the default for those > is > imnsho asking for troubles without clear benefit (experimental evidence > suggests that smsc etherpower II grows older more easily than plain pci > 8169 :o/ ). > > I'd rather leave these alone and change the default for the PCI Express > chipsets. > Btw, while it does not seem to hurt, they should not need any CPlusCmd Dual > Access Cycle tweak either. Realtek may establish it (Lin ?)
You don't have to set CPlusCmd Dual Access Cycle for the PCI Express chipsets. ------Please consider the environment before printing this e-mail.
