From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: [PATCH v4 09/11] x86/intel_pstate: add a booting param to select the driver to load Date: Fri, 24 Jul 2015 07:58:40 -0600 Message-ID: <55B260B00200007800095395@prv-mh.provo.novell.com> References: <1435231021-22719-1-git-send-email-wei.w.wang@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1435231021-22719-1-git-send-email-wei.w.wang@intel.com> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Wei Wang Cc: andrew.cooper3@citrix.com, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org >>> On 25.06.15 at 13:17, wrote: > By default, the old P-state driver (acpi-freq) is used. Adding > "intel_pstate" to the Xen booting param list to enable the > use of intel_pstate. However, if intel_pstate is enabled on a > machine which does not support the driver (e.g. Nehalem), the > old P-state driver will be loaded due to the failure loading of > intel_pstate. > > Also, adding the intel_pstate booting parameter to > xen-command-line.markdown. > > v4 changes: > 1) moved the definition of "load_intel_pstate" right ahead of > intel_pstate_init(); Didn't I ask for it to be moved _inside_ the function? > --- a/xen/arch/x86/acpi/cpufreq/intel_pstate.c > +++ b/xen/arch/x86/acpi/cpufreq/intel_pstate.c > @@ -831,12 +831,18 @@ static void __init copy_cpu_funcs(struct pstate_funcs *funcs) > pstate_funcs.get_vid = funcs->get_vid; > } > > +static bool_t __initdata load_intel_pstate; > +boolean_param("intel_pstate", load_intel_pstate); > + > int __init intel_pstate_init(void) > { > int cpu, rc = 0; > const struct x86_cpu_id *id; > struct cpu_defaults *cpu_info; > > + if (!load_intel_pstate) > + return -ENODEV; > + With the variable then perhaps simply be named "load"? Jan