[PATCH i-g-t 1/2] lib/igt_psr: add helper to check of given psr mode can be enabled

[Joshi, Kunal1]

Hell bhanu

-----Original Message-----
From: Modem, Bhanuprakash <bhanuprakash.modem at intel.com> 
Sent: Wednesday, January 24, 2024 5:28 PM
To: Joshi, Kunal1 <kunal1.joshi at intel.com>; igt-dev at lists.freedesktop.org
Cc: B, Jeevan <jeevan.b at intel.com>
Subject: Re: [PATCH i-g-t 1/2] lib/igt_psr: add helper to check of given psr mode can be enabled

Hi Kunal,

On 24-01-2024 04:04 pm, Kunal Joshi wrote:
> Check if given psr mode can be enabled by reading enable_psr modparam
> 
> Cc: Jeevan B <jeevan.b at intel.com>
> Cc: Bhanuprakash Modem <bhanuprakash.modem at intel.com>
> Signed-off-by: Kunal Joshi <kunal1.joshi at intel.com>
> Reviewed-by: Jeevan B <jeevan.b at intel.com>
> ---
>   lib/igt_psr.c | 20 ++++++++++++++++++++
>   lib/igt_psr.h |  1 +
>   2 files changed, 21 insertions(+)
> 
> diff --git a/lib/igt_psr.c b/lib/igt_psr.c index 663bac163..ac214fcfc 
> 100644
> --- a/lib/igt_psr.c
> +++ b/lib/igt_psr.c
> @@ -394,3 +394,23 @@ enum psr_mode psr_get_mode(int debugfs_fd)
>   
>   	return PSR_DISABLED;
>   }
> +
> +/**
> + * is_psr_enable_possible
> + * Check if given psr mode can be enabled by reading enable_psr
> + * modparam
> + *
> + * Returns:
> + * True if given psr mode can be enabled, false otherwise.
> + */
> +bool is_psr_enable_possible(int drm_fd, enum psr_mode mode) {
> +	char *param_value;
> +	int enable_psr;
> +
> +	param_value = __igt_params_get(drm_fd, "enable_psr");
> +	igt_assert_f(param_value, "Could not read enable_psr modparam\n");

IMHO, Please don't assert here. Instead, allow the user to decide if modparam "enable_psr" is not available.

- Bhanu

I think it's fine to assert since we expect enable_psr to be present,
since the caller may not handle this, one less thing to worry 😊

I can see this is done similarly at many place 
example :- intel_pipe_output_combo_valid

> +	enable_psr = atoi(param_value);
> +	free(param_value);
> +	return enable_psr > mode;
> +}
> diff --git a/lib/igt_psr.h b/lib/igt_psr.h index 36711c0d4..82a4e8c5e 
> 100644
> --- a/lib/igt_psr.h
> +++ b/lib/igt_psr.h
> @@ -61,5 +61,6 @@ bool i915_psr2_selective_fetch_check(int drm_fd);
>   
>   bool i915_psr2_sel_fetch_to_psr1(int drm_fd);
>   void i915_psr2_sel_fetch_restore(int drm_fd);
> +bool is_psr_enable_possible(int drm_fd, enum psr_mode mode);
>   
>   #endif[
Thanks and Regards
[Kunal Joshi]