From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Message-ID: <29827fcdcdd4fb46b680a6bd184b44fca638666e.camel@redhat.com> Subject: Re: [PATCH 03/17] fpga: dfl: fme: support 512bit data width PR From: Scott Wood Date: Wed, 27 Mar 2019 01:10:31 -0500 In-Reply-To: <20190327043743.GA20968@hao-dev> References: <1553483264-5379-1-git-send-email-hao.wu@intel.com> <1553483264-5379-4-git-send-email-hao.wu@intel.com> <127a9356a7bf597d35dd361f2b16bf80460f0370.camel@redhat.com> <655bf2991a4f8bf6a473c91218d6dba7748520aa.camel@redhat.com> <580c6c604d3915c105f076fc7f22ab5da98598fc.camel@redhat.com> <20190327043743.GA20968@hao-dev> Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit To: Wu Hao Cc: Alan Tull , Moritz Fischer , linux-fpga@vger.kernel.org, linux-kernel , linux-api@vger.kernel.org, Ananda Ravuri , Xu Yilun List-ID: On Wed, 2019-03-27 at 12:37 +0800, Wu Hao wrote: > On Tue, Mar 26, 2019 at 04:22:34PM -0500, Scott Wood wrote: > > On Tue, 2019-03-26 at 14:33 -0500, Alan Tull wrote: > > > On Mon, Mar 25, 2019 at 5:58 PM Scott Wood wrote: > > > > > > > > Hi Scott, > > > > > > > On Mon, 2019-03-25 at 17:53 -0500, Scott Wood wrote: > > > > > On Mon, 2019-03-25 at 11:07 +0800, Wu Hao wrote: > > > > > > +#else > > > > > > +static inline void copy512(void *src, void __iomem *dst) > > > > > > +{ > > > > > > + WARN_ON_ONCE(1); > > > > > > +} > > > > > > +#endif > > > > > Likewise, this will be called if a revision 2 device is used on non- > > > > > x86 > > > > > (or on x86 with an old binutils). The driver should fall back to > > > > > 32- > > > > > bit > > > > > in such cases. > > Unfortunately revision 2 is only for integrated FPGA solution, and it > doesn't > support any fallback solution (original 32bit data partial reconfiguration > is > not supported any more), so driver has to WARN in such path. >From the commit message it seemed like this was just an optimization, not something necessary to support revision 2. If there's no way to program the device without AVX512, then printing an error message and returning an error to userspace would be better than WARN_ON, since it's not actually a kernel bug. -Scott