> -----Original Message----- > From: linux-acpi-owner(a)vger.kernel.org <linux-acpi-owner(a)vger.kernel.org&gt; On Behalf Of Pandruvada, Srinivas > Sent: Wednesday, March 27, 2019 10:48 AM > To: linux-kernel(a)vger.kernel.org; devel(a)acpica.org; Natarajan, Janakarajan <Janakarajan.Natarajan(a)amd.com&gt;; linux- > acpi(a)vger.kernel.org; linux-pm(a)vger.kernel.org > Cc: Ghannam, Yazen <Yazen.Ghannam(a)amd.com&gt;; lenb(a)kernel.org; viresh.kumar(a)linaro.org; Moore, Robert > <robert.moore(a)intel.com&gt;; Schmauss, Erik <erik.schmauss(a)intel.com&gt;; rjw(a)rjwysocki.net > Subject: Re: [PATCH 5/6] acpi/cppc: Add support for optional CPPC registers > > On Fri, 2019-03-22 at 20:26 +0000, Natarajan, Janakarajan wrote: > > From: Yazen Ghannam <Yazen.Ghannam(a)amd.com&gt; > > > > Newer AMD processors support a subset of the optional CPPC registers. > > Create show, store and helper routines for supported CPPC registers. > > > > Signed-off-by: Yazen Ghannam <Yazen.Ghannam(a)amd.com&gt; > > [ carved out into a patch, cleaned up, productized ] > > Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan(a)amd.com&gt; > > > > [..] > > > + /* desired_perf is the only mandatory value in perf_ctrls */ > > + if (cpc_read(cpu, desired_reg, &desired)) > > + ret = -EFAULT; > > + > > + if (CPC_SUPPORTED(max_reg) && cpc_read(cpu, max_reg, &max)) > > + ret = -EFAULT; > > + > We should create and use different macro other than CPPC_SUPPORTED. > CPC_SUPPORTED doesn't validate the correctness of object type for a > field. For example "Maximum Performance Register" can only be buffer > not integer. In this way invalid field definitions can be ignored. > So create something like "CPPC_SUPPORTED_BUFFER" for buffer-only registers? And then buffer/integer registers will continue to use "CPPC_SUPPORTED". These seem to be the only two cases at this time. Is this okay?