Re:[PATCH RESENT] cpufreq: amd-pstate: add quirk for Ryzen 3000 series processor

["David Wang" <00107082@163.com>]

Hi, 

At 2024-08-09 14:09:05, "Perry Yuan" <perry.yuan@amd.com> wrote:
>The Ryzen 3000 series processors have been observed lacking the
>nominal_freq and lowest_freq parameters in their ACPI tables. This
>absence causes issues with loading the amd-pstate driver on these
>systems. Introduces a fix to resolve the dependency issue
>by adding a quirk specifically for the Ryzen 3000 series.
>
>Reported-by: David Wang <00107082@163.com>
>Signed-off-by: Perry Yuan <perry.yuan@amd.com>
>---
> drivers/cpufreq/amd-pstate.c | 30 ++++++++++++++++++++++++++++++
> 1 file changed, 30 insertions(+)
>
>diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
>index 68c616b572f2..b39365b980b9 100644
>--- a/drivers/cpufreq/amd-pstate.c
>+++ b/drivers/cpufreq/amd-pstate.c
>@@ -142,6 +142,11 @@ static struct quirk_entry quirk_amd_7k62 = {
> 	.lowest_freq = 550,
> };
> 
>+static struct quirk_entry quirk_amd_mts = {
>+	.nominal_freq = 3600,
>+	.lowest_freq = 550,
>+};
>+
> static int __init dmi_matched_7k62_bios_bug(const struct dmi_system_id *dmi)
> {
> 	/**
>@@ -158,6 +163,21 @@ static int __init dmi_matched_7k62_bios_bug(const struct dmi_system_id *dmi)
> 	return 0;
> }
> 
>+static int __init dmi_matched_mts_bios_bug(const struct dmi_system_id *dmi)
>+{
>+	/**
>+	 * match the broken bios for ryzen 3000 series processor support CPPC V2
>+	 * broken BIOS lack of nominal_freq and lowest_freq capabilities
>+	 * definition in ACPI tables
>+	 */
>+	if (cpu_feature_enabled(X86_FEATURE_ZEN2)) {
>+		quirks = dmi->driver_data;
>+		pr_info("Overriding nominal and lowest frequencies for %s\n", dmi->ident);
>+		return 1;
>+	}
>+
>+	return 0;
>+}
> static const struct dmi_system_id amd_pstate_quirks_table[] __initconst = {
> 	{
> 		.callback = dmi_matched_7k62_bios_bug,
>@@ -168,6 +188,16 @@ static const struct dmi_system_id amd_pstate_quirks_table[] __initconst = {
> 		},
> 		.driver_data = &quirk_amd_7k62,
> 	},
>+	{
>+		.callback = dmi_matched_mts_bios_bug,
>+		.ident = "AMD Ryzen 3000",
>+		.matches = {
>+			DMI_MATCH(DMI_PRODUCT_NAME, "B450M MORTAR MAX (MS-7B89)"),
>+			DMI_MATCH(DMI_BIOS_RELEASE, "06/10/2020"),
>+			DMI_MATCH(DMI_BIOS_VERSION, "5.14"),
>+		},
>+		.driver_data = &quirk_amd_mts,
>+	},
> 	{}
> };
> MODULE_DEVICE_TABLE(dmi, amd_pstate_quirks_table);
>-- 
>2.34.1


I tried this patch on 6.11.0-rc2, sadly this config does not match my system (BIOS).
After some correction, I confirm following configuration matches my BIOS:

 static const struct dmi_system_id amd_pstate_quirks_table[] __initconst = {
        {
                .callback = dmi_matched_7k62_bios_bug,
@@ -168,6 +190,16 @@ static const struct dmi_system_id amd_pstate_quirks_table[] __initconst = {
                },
                .driver_data = &quirk_amd_7k62,
        },
+       {
+               .callback = dmi_matched_mts_bios_bug,
+               .ident = "AMD Ryzen 3000",
+               .matches = {
+                       DMI_MATCH(DMI_PRODUCT_NAME, "MS-7B89"),
+                       DMI_MATCH(DMI_BIOS_RELEASE, "5.14"),
+                       DMI_MATCH(DMI_BIOS_VERSION, "2.80"),
+               },
+               .driver_data = &quirk_amd_mts,
+       },
        {}
 };
 MODULE_DEVICE_TABLE(dmi, amd_pstate_quirks_table);

And with this change, my system boots with no amd_pstate error. 
The old warning and a new info show up though, I guess that is acceptable?

[Fri Aug  9 19:35:29 2024] amd_pstate: The CPPC feature is supported but currently disabled by the BIOS.
                           Please enable it if your BIOS has the CPPC option.
[Fri Aug  9 19:35:29 2024] amd_pstate: Overriding nominal and lowest frequencies for AMD Ryzen 3000


This patch confuses me a little,
I do not see any bound between CPU identity "AMD Ryzen 3000" and my BIOS DMIs,
 it make no sense to me to infer the CPU identity just by some BIOS DMIs. 
What if another AMD CPU with different cpu frequency range installed on the same BIOS as mine?
(I guess current assumption is that my BIOS is way too old and weird, the possibility of "what if" mentioned above is very low?)


Anyway, after patching my system with a proper quirk,
I dose not notice any significant CPU performance changes,  yet. (My kernel build time dose not change much, at least)
And it seems to me that the amd_pstate module is active:

$ ls /sys/devices/system/cpu/cpufreq/policy0/*amd* -l
-r--r--r-- 1 root root 4096 Aug  9 20:46 /sys/devices/system/cpu/cpufreq/policy0/amd_pstate_highest_perf
-r--r--r-- 1 root root 4096 Aug  9 20:46 /sys/devices/system/cpu/cpufreq/policy0/amd_pstate_hw_prefcore
-r--r--r-- 1 root root 4096 Aug  9 20:46 /sys/devices/system/cpu/cpufreq/policy0/amd_pstate_lowest_nonlinear_freq
-r--r--r-- 1 root root 4096 Aug  9 20:46 /sys/devices/system/cpu/cpufreq/policy0/amd_pstate_max_freq
-r--r--r-- 1 root root 4096 Aug  9 20:46 /sys/devices/system/cpu/cpufreq/policy0/amd_pstate_prefcore_ranking

 $ cpupower frequency-info  # when my system is idle
analyzing CPU 0:
  driver: amd-pstate-epp
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency:  Cannot determine or is not supported.
  hardware limits: 550 MHz - 3.91 GHz
  available cpufreq governors: performance powersave
  current policy: frequency should be within 550 MHz and 3.91 GHz.
                  The governor "powersave" may decide which speed to use
                  within this range.
  current CPU frequency: Unable to call hardware 
  current CPU frequency: 550 MHz (asserted by call to kernel)
  boost state support:
    Supported: yes
    Active: no

$ cpupower frequency-info  # when my sytem is busy building kernel
analyzing CPU 0:
  driver: amd-pstate-epp
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency:  Cannot determine or is not supported.
  hardware limits: 550 MHz - 3.91 GHz
  available cpufreq governors: performance powersave
  current policy: frequency should be within 550 MHz and 3.91 GHz.
                  The governor "powersave" may decide which speed to use
                  within this range.
  current CPU frequency: Unable to call hardware
  current CPU frequency: 3.89 GHz (asserted by call to kernel)
  boost state support:
    Supported: yes
    Active: no


FYI
And thanks for your support tailoring for my system~!
David