| Message ID | 20201210142139.20490-1-yousaf.kaukab@suse.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/2] acpi: cppc: add cpufreq device | expand |
Hi guys, On Thursday 10 Dec 2020 at 15:32:09 (+0100), Rafael J. Wysocki wrote: > On Thu, Dec 10, 2020 at 3:23 PM Mian Yousaf Kaukab > <yousaf.kaukab@suse.com> wrote: > > > > From: Mian Yousaf Kaukab <ykaukab@suse.de> > > > > Since commit 28f06f770454 ("cppc_cpufreq: replace per-cpu structures with > > lists"), cppc-cpufreq driver doesn't check availability of PSD data before > > registering with cpufreq core. As a result on a ThunderX2 platform when > > CPPC is disabled from BIOS, kernel log is spammed with following messages: > > > > [ 180.974166] CPPC Cpufreq: Error in acquiring _CPC/_PSD data for CPUxx > > > > acpi_cppc_processor_probe() never succeed in this case because > > acpi_evaluate_object_typed("_CPC") always returns AE_NOT_FOUND. When > > cpufreq core calls cppc_cpufreq_cpu_init(), driver fails to obtain PSD data > > and print error messages. > > > > Convert cppc-cpufreq driver to a platform driver (done in a separate patch) > > and add cppc-cpufreq device when acpi_cppc_processor_probe() succeeds. > > Honestly, I prefer to drop 28f06f770454 (along with its follower) > instead of making this change. > > > Fixes: 28f06f770454 ("cppc_cpufreq: replace per-cpu structures with lists") > Sorry for introducing this, I though it was enough to bail out of cpu init if _CPC entries are not present. I'll defer to Rafael to decide whether to drop the patches or accept alternative fixes, but I believe the rework of the data structures and initialisation is useful. As alternative fix, would it be okay to introduce a check function to verify for !cpc_ptr, to be called in cppc_cpufreq_init()? In that case the driver would not be registered if this check fails. Thanks, Ionela. > Thanks!
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index 4e478f751ff7..adf9ca3be9fe 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -39,6 +39,7 @@ #include <linux/ktime.h> #include <linux/rwsem.h> #include <linux/wait.h> +#include <linux/platform_device.h> #include <acpi/cppc_acpi.h> @@ -606,6 +607,23 @@ static bool is_cppc_supported(int revision, int num_ent) return true; } +static void add_cppc_cpufreq_dev(void) +{ + static bool already_added; + + if (!already_added) { + struct platform_device *pdev; + + pdev = platform_device_register_simple("cppc-cpufreq", -1, + NULL, 0); + if (IS_ERR(pdev)) + pr_err("Couldn't register cppc-cpufreq err=%ld\n", + PTR_ERR(pdev)); + else + already_added = true; + } +} + /* * An example CPC table looks like the following. * @@ -815,6 +833,9 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr) } kfree(output.pointer); + + add_cppc_cpufreq_dev(); + return 0; out_free: