Re: [UPDATE][PATCH] platform/x86/intel-uncore-freq: Conditionally create attribute for read frequency

From: Hans de Goede <hdegoede@redhat.com>
To: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
	markgross@kernel.org, ilpo.jarvinen@linux.intel.com,
	andriy.shevchenko@linux.intel.com
Cc: platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [UPDATE][PATCH] platform/x86/intel-uncore-freq: Conditionally create attribute for read frequency
Date: Thu, 5 Oct 2023 09:03:20 +0200	[thread overview]
Message-ID: <e84bc80e-1fd9-f07b-526a-b4eb4780ea9b@redhat.com> (raw)
In-Reply-To: <20231004181915.1887913-1-srinivas.pandruvada@linux.intel.com>

Hi Srinivas,

On 10/4/23 20:19, Srinivas Pandruvada wrote:
> When the current uncore frequency can't be read, don't create attribute
> "current_freq_khz" as any read will fail later. Some user space
> applications like turbostat fail to continue with the failure. So, check
> error during attribute creation.
> 
> Fixes: 414eef27283a ("platform/x86/intel/uncore-freq: Display uncore current frequency")
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> ---
> Added fixes tag which added current_freq_khz. But after this
> tag there is reorg of code, so need manual backport for some versions.
> I will separately submit to stable trees after merge.

Can you for future updated patches please use the ususal [PATCH v2],
[PATCH v3], etc. prefix ?

Also please document the changes per version after the cutline, e.g. :

```
---
Changes in v2:
- Added fixes tag which added current_freq_khz. Note after this
  tag there is reorg of code, so need manual backport for some versions.
  I will separately submit to stable trees after merge.
```

Regards,

Hans

> 
>  .../x86/intel/uncore-frequency/uncore-frequency-common.c  | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c
> index 1152deaa0078..33ab207493e3 100644
> --- a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c
> +++ b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c
> @@ -176,7 +176,7 @@ show_uncore_data(initial_max_freq_khz);
>  
>  static int create_attr_group(struct uncore_data *data, char *name)
>  {
> -	int ret, index = 0;
> +	int ret, freq, index = 0;
>  
>  	init_attribute_rw(max_freq_khz);
>  	init_attribute_rw(min_freq_khz);
> @@ -197,7 +197,11 @@ static int create_attr_group(struct uncore_data *data, char *name)
>  	data->uncore_attrs[index++] = &data->min_freq_khz_dev_attr.attr;
>  	data->uncore_attrs[index++] = &data->initial_min_freq_khz_dev_attr.attr;
>  	data->uncore_attrs[index++] = &data->initial_max_freq_khz_dev_attr.attr;
> -	data->uncore_attrs[index++] = &data->current_freq_khz_dev_attr.attr;
> +
> +	ret = uncore_read_freq(data, &freq);
> +	if (!ret)
> +		data->uncore_attrs[index++] = &data->current_freq_khz_dev_attr.attr;
> +
>  	data->uncore_attrs[index] = NULL;
>  
>  	data->uncore_attr_group.name = name;