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From:   Jani Nikula <jani.nikula@linux.intel.com>
To:     Colin Ian King <colin.i.king@gmail.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Cc:     kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org,
        Vandita Kulkarni <vandita.kulkarni@intel.com>,
        Manasi Navare <manasi.d.navare@intel.com>
Subject: Re: [PATCH] drm/i915: make a handful of read-only arrays static const
In-Reply-To: <20220222120323.86480-1-colin.i.king@gmail.com>
Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
References: <20220222120323.86480-1-colin.i.king@gmail.com>
Date:   Tue, 22 Feb 2022 14:43:22 +0200
Message-ID: <87tucr6phx.fsf@intel.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

On Tue, 22 Feb 2022, Colin Ian King <colin.i.king@gmail.com> wrote:
> Don't populate the read-only arrays on the stack but instead make
> them static const. Also makes the object code a little smaller.
> Reformat the statements to clear up checkpatch warning.
>
> Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
> ---
>  drivers/gpu/drm/i915/display/intel_vdsc.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c b/drivers/gpu/drm/i915/display/intel_vdsc.c
> index 3faea903b9ae..d49f66237ec3 100644
> --- a/drivers/gpu/drm/i915/display/intel_vdsc.c
> +++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
> @@ -378,10 +378,18 @@ calculate_rc_params(struct rc_parameters *rc,
>  {
>  	int bpc = vdsc_cfg->bits_per_component;
>  	int bpp = vdsc_cfg->bits_per_pixel >> 4;
> -	int ofs_und6[] = { 0, -2, -2, -4, -6, -6, -8, -8, -8, -10, -10, -12, -12, -12, -12 };
> -	int ofs_und8[] = { 2, 0, 0, -2, -4, -6, -8, -8, -8, -10, -10, -10, -12, -12, -12 };
> -	int ofs_und12[] = { 2, 0, 0, -2, -4, -6, -8, -8, -8, -10, -10, -10, -12, -12, -12 };
> -	int ofs_und15[] = { 10, 8, 6, 4, 2, 0, -2, -4, -6, -8, -10, -10, -12, -12, -12 };
> +	static const int ofs_und6[] = {
> +		0, -2, -2, -4, -6, -6, -8, -8, -8, -10, -10, -12, -12, -12, -12
> +	};
> +	static const int ofs_und8[] = {
> +		2, 0, 0, -2, -4, -6, -8, -8, -8, -10, -10, -10, -12, -12, -12
> +	};
> +	static const int ofs_und12[] = {
> +		2, 0, 0, -2, -4, -6, -8, -8, -8, -10, -10, -10, -12, -12, -12
> +	};

Hmm, I wonder why the same values are duplicated in ofs_und8 and
ofs_und12. Cc: Vandita, Manasi.

Regardless, the patch is sane.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> +	static const int ofs_und15[] = {
> +		10, 8, 6, 4, 2, 0, -2, -4, -6, -8, -10, -10, -12, -12, -12
> +	};
>  	int qp_bpc_modifier = (bpc - 8) * 2;
>  	u32 res, buf_i, bpp_i;

-- 
Jani Nikula, Intel Open Source Graphics Center