[PATCH] powercap: RAPL: Add Power Limit4 support for Meteor Lake SoC

[PATCH] powercap: RAPL: Add Power Limit4 support for Meteor Lake SoC

[Sumeet Pawnikar]

Add Meteor Lake SoC to the list of processor models for which
Power Limit4 is supported by the Intel RAPL driver.

Signed-off-by: Sumeet Pawnikar <sumeet.r.pawnikar@intel.com>
---
 drivers/powercap/intel_rapl_msr.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/powercap/intel_rapl_msr.c b/drivers/powercap/intel_rapl_msr.c
index bc6adda58883..a27673706c3d 100644
--- a/drivers/powercap/intel_rapl_msr.c
+++ b/drivers/powercap/intel_rapl_msr.c
@@ -143,6 +143,8 @@ static const struct x86_cpu_id pl4_support_ids[] = {
 	{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ALDERLAKE_N, X86_FEATURE_ANY },
 	{ X86_VENDOR_INTEL, 6, INTEL_FAM6_RAPTORLAKE, X86_FEATURE_ANY },
 	{ X86_VENDOR_INTEL, 6, INTEL_FAM6_RAPTORLAKE_P, X86_FEATURE_ANY },
+	{ X86_VENDOR_INTEL, 6, INTEL_FAM6_METEORLAKE, X86_FEATURE_ANY },
+	{ X86_VENDOR_INTEL, 6, INTEL_FAM6_METEORLAKE_L, X86_FEATURE_ANY },
 	{}
 };
 
-- 
2.17.1

Re: [PATCH] powercap: RAPL: Add Power Limit4 support for Meteor Lake SoC

[Rafael J. Wysocki]

On Wed, Feb 15, 2023 at 1:46 PM Sumeet Pawnikar
<sumeet.r.pawnikar@intel.com> wrote:
>
> Add Meteor Lake SoC to the list of processor models for which
> Power Limit4 is supported by the Intel RAPL driver.
>
> Signed-off-by: Sumeet Pawnikar <sumeet.r.pawnikar@intel.com>
> ---
>  drivers/powercap/intel_rapl_msr.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/powercap/intel_rapl_msr.c b/drivers/powercap/intel_rapl_msr.c
> index bc6adda58883..a27673706c3d 100644
> --- a/drivers/powercap/intel_rapl_msr.c
> +++ b/drivers/powercap/intel_rapl_msr.c
> @@ -143,6 +143,8 @@ static const struct x86_cpu_id pl4_support_ids[] = {
>         { X86_VENDOR_INTEL, 6, INTEL_FAM6_ALDERLAKE_N, X86_FEATURE_ANY },
>         { X86_VENDOR_INTEL, 6, INTEL_FAM6_RAPTORLAKE, X86_FEATURE_ANY },
>         { X86_VENDOR_INTEL, 6, INTEL_FAM6_RAPTORLAKE_P, X86_FEATURE_ANY },
> +       { X86_VENDOR_INTEL, 6, INTEL_FAM6_METEORLAKE, X86_FEATURE_ANY },
> +       { X86_VENDOR_INTEL, 6, INTEL_FAM6_METEORLAKE_L, X86_FEATURE_ANY },
>         {}
>  };
>
> --

Applied as 6.3-rc material, thanks!

Re: [PATCH] powercap: RAPL: Add Power Limit4 support for Meteor Lake SoC

[Dave Hansen]

On 2/15/23 04:32, Sumeet Pawnikar wrote:
> diff --git a/drivers/powercap/intel_rapl_msr.c b/drivers/powercap/intel_rapl_msr.c
> index bc6adda58883..a27673706c3d 100644
> --- a/drivers/powercap/intel_rapl_msr.c
> +++ b/drivers/powercap/intel_rapl_msr.c
> @@ -143,6 +143,8 @@ static const struct x86_cpu_id pl4_support_ids[] = {
>  	{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ALDERLAKE_N, X86_FEATURE_ANY },
>  	{ X86_VENDOR_INTEL, 6, INTEL_FAM6_RAPTORLAKE, X86_FEATURE_ANY },
>  	{ X86_VENDOR_INTEL, 6, INTEL_FAM6_RAPTORLAKE_P, X86_FEATURE_ANY },
> +	{ X86_VENDOR_INTEL, 6, INTEL_FAM6_METEORLAKE, X86_FEATURE_ANY },
> +	{ X86_VENDOR_INTEL, 6, INTEL_FAM6_METEORLAKE_L, X86_FEATURE_ANY },
>  	{}
>  };

Sumeet, could you _please_ go take a close look at 'struct x86_cpu_id'?

> struct x86_cpu_id {
>         __u16 vendor;
>         __u16 family;
>         __u16 model;
>         __u16 steppings;
>         __u16 feature;  /* bit index */
>         kernel_ulong_t driver_data;
> };

You might also want to very carefully count the fields in the structure.
 Which field is being initialized to X86_FEATURE_ANY?  Is it:

 a. ->feature
 b. ->steppings
 c. ->model

How could this _possibly_ work, you ask yourself?  Well, you lucked out:

#define X86_FAMILY_ANY   0
#define X86_MODEL_ANY    0
#define X86_STEPPING_ANY 0
#define X86_FEATURE_ANY  0

so, you actually accidentally *explicitly* specified a 0 for ->steppings
*AND* accidentally *implicitly* specified a 0 for ->feature.

... and you did this in at least five separate commits over four years.

Why does this matter?  Because some hapless maintainer might take your
code, copy it, and then s/X86_FEATURE_ANY/X86_FEATURE_FOO/ and then
scratch their head for an hour as to why it doesn't work.

Could you please fix this up?  As penance, you could even fix the _ANY
defines so that people can't do this accidentally any longer.

Re: [PATCH] powercap: RAPL: Add Power Limit4 support for Meteor Lake SoC

[Tony Luck]

On Thu, May 11, 2023 at 07:55:08AM -0700, Dave Hansen wrote:
> Could you please fix this up?  As penance, you could even fix the _ANY
> defines so that people can't do this accidentally any longer.

See the X86_MATCH_INTEL_FAM6_MODEL() for how to do this right.

-Tony

RE: [PATCH] powercap: RAPL: Add Power Limit4 support for Meteor Lake SoC

[Pawnikar, Sumeet R]

> -----Original Message-----
> From: Luck, Tony <tony.luck@intel.com>
> Sent: Thursday, May 11, 2023 10:15 PM
> To: Hansen, Dave <dave.hansen@intel.com>
> Cc: Pawnikar, Sumeet R <sumeet.r.pawnikar@intel.com>; rafael@kernel.org;
> srinivas.pandruvada@linux.intel.com; Zhang, Rui <rui.zhang@intel.com>;
> linux-pm@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] powercap: RAPL: Add Power Limit4 support for Meteor
> Lake SoC
> 
> On Thu, May 11, 2023 at 07:55:08AM -0700, Dave Hansen wrote:
> > Could you please fix this up?  As penance, you could even fix the _ANY
> > defines so that people can't do this accidentally any longer.
> 
> See the X86_MATCH_INTEL_FAM6_MODEL() for how to do this right.
> 

Thanks Dave and Tony for this information. 
Let me check and submit the fix for this. 

Regards, 
Sumeet. 

> -Tony