Re: [dpdk-dev] [PATCH v3 3/6] ena: disable readless communication regarding to HW revision

[Bruce Richardson <bruce.richardson@intel.com>]

On Tue, Jul 05, 2016 at 12:02:41PM +0200, Jan Mędala wrote:
> Bruce,
> 
> Here's explanation of readless communication (on behalf of Alex):
> 
> > "readless" refers to ability to read ENA registers without actually
> > issuing read request from host (x86).
> > Instead, host programs 2 registers on device that trigger DMA from device
> > to host and report register value.
> > However, this functionality is not going to be available in all type of
> > devices. The decision if this mode is supported or not , is taken from
> > revision_id in pci configuration space.
> 
> 

Thanks, I'll add this into the commit message to help explain things to anyone
looking at the commit later.

/Bruce

> Regards
> 
>   Jan
> 
> 2016-07-04 17:43 GMT+02:00 Bruce Richardson <bruce.richardson@intel.com>:
> 
> > On Thu, Jun 30, 2016 at 05:04:56PM +0200, Jan Medala wrote:
> > > Depending on HW revision readless communcation between host and device
> > > may be unavailable.
> > > In that case prevent PMD of seting up readless communication mechanism.
> > >
> > The idea of readless communication is a strange one. Can you provide a bit
> > more detail as to what "readless communication" refers to.
> >
> > /Bruce
> >