Re: [BISECTED REGRESSION] b43legacy broken on G4 PowerBook
From: Benjamin Herrenschmidt
Date: Tue Jun 11 2019 - 03:03:05 EST
On Tue, 2019-06-11 at 08:08 +0200, Christoph Hellwig wrote:
> On Tue, Jun 11, 2019 at 03:56:33PM +1000, Benjamin Herrenschmidt
> > The reason I think it sort-of-mostly-worked is that to get more
> > than
> > 1GB of RAM, those machines use CONFIG_HIGHMEM. And *most* network
> > buffers aren't allocated in Highmem.... so you got lucky.
> > That said, there is such as thing as no-copy send on network, so I
> > wouldn't be surprised if some things would still have failed, just
> > not
> > frequent enough for you to notice.
> Unless NETIF_F_HIGHDMA is set on a netdev, the core networkign code
> will bounce buffer highmem pages for the driver under all
... which b43legacy doesn't set to the best of my knowledge ...
Which makes me wonder how come it didn't work even with your patches ?
AFAIK, we have less than 1GB of lowmem unless the config has been