> -----Original Message----- > From: [email protected] [mailto:gpxe-devel- > [email protected]] On Behalf Of Guo-Fu Tseng > Sent: Saturday, May 29, 2010 1:35 AM > To: Michael Brown; [email protected] > Subject: Re: [gPXE-devel] [PATCH] [jme] Adding JMicron Ethernet driver > > On Sat, 29 May 2010 01:04:52 +0100, Michael Brown wrote > > On Friday 28 May 2010 18:27:00 [email protected] wrote: > > > A new driver for JMicron Ethernet controller. > > > > Looks pretty nice! :) > > > > A few comments, based on a very quick look: > > > > > +#if __x86_64__ > > > + rxdesc->desc1.flags = RXFLAG_64BIT; > > > +#endif > > > > What does this flag actually do? It's implausible that the card cares > > which CPU is running on the host system. > Ahh... Forget to remove it. > It was intended for preventing gPXE provide over 4G DMA > address on x86_64 arch. Since the gPXE won't provide any > address above 4G, this FLAG is not needed.
Currently, it is possible to have a DMA buffer located above 4GB when the system is 64-bit EFI. (However, it seems that other drivers don't deal with this situation correctly, and it might be easier to modify malloc_dma to impose this limit across all build types.) _______________________________________________ gPXE-devel mailing list [email protected] http://etherboot.org/mailman/listinfo/gpxe-devel
