Re: [PATCH] drm/i915/audio: constify ELD pointers

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Jani Nikula <jani.nikula@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915/audio: constify ELD pointers
Date: Tue, 19 Jun 2018 16:09:46 +0300	[thread overview]
Message-ID: <20180619130946.GH20518@intel.com> (raw)
In-Reply-To: <20180619124437.10982-1-jani.nikula@intel.com>

On Tue, Jun 19, 2018 at 03:44:37PM +0300, Jani Nikula wrote:
> The hooks aren't supposed to modify the ELD, so use const pointer. As a
> drive-by fix, use drm_eld_size() to log ELD size.
> 
> Suggested-by: Ville Syrjala <ville.syrjala@linux.intel.com>
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_audio.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
> index a34aa66f28f8..bb94172ffc07 100644
> --- a/drivers/gpu/drm/i915/intel_audio.c
> +++ b/drivers/gpu/drm/i915/intel_audio.c
> @@ -213,7 +213,7 @@ static bool intel_eld_uptodate(struct drm_connector *connector,
>  			       i915_reg_t reg_edid)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(connector->dev);
> -	u8 *eld = connector->eld;
> +	const u8 *eld = connector->eld;
>  	u32 tmp;
>  	int i;
>  
> @@ -228,7 +228,7 @@ static bool intel_eld_uptodate(struct drm_connector *connector,
>  	I915_WRITE(reg_elda, tmp);
>  
>  	for (i = 0; i < drm_eld_size(eld) / 4; i++)
> -		if (I915_READ(reg_edid) != *((u32 *)eld + i))
> +		if (I915_READ(reg_edid) != *((const u32 *)eld + i))

I was hoping we could make it const u32* and kill these ugly casts.
But I suppose that would require more casts for the drm_eld_size() & co.,
or changing those to take a const void* instead.

Anyways, the const alone is an improvement so
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

>  			return false;
>  
>  	return true;
> @@ -261,12 +261,12 @@ static void g4x_audio_codec_enable(struct intel_encoder *encoder,
>  {
>  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
>  	struct drm_connector *connector = conn_state->connector;
> -	u8 *eld = connector->eld;
> +	const u8 *eld = connector->eld;
>  	u32 eldv;
>  	u32 tmp;
>  	int len, i;
>  
> -	DRM_DEBUG_KMS("Enable audio codec, %u bytes ELD\n", eld[2]);
> +	DRM_DEBUG_KMS("Enable audio codec, %u bytes ELD\n", drm_eld_size(eld));
>  
>  	tmp = I915_READ(G4X_AUD_VID_DID);
>  	if (tmp == INTEL_AUDIO_DEVBLC || tmp == INTEL_AUDIO_DEVCL)
> @@ -288,7 +288,7 @@ static void g4x_audio_codec_enable(struct intel_encoder *encoder,
>  	len = min(drm_eld_size(eld) / 4, len);
>  	DRM_DEBUG_DRIVER("ELD size %d\n", len);
>  	for (i = 0; i < len; i++)
> -		I915_WRITE(G4X_HDMIW_HDMIEDID, *((u32 *)eld + i));
> +		I915_WRITE(G4X_HDMIW_HDMIEDID, *((const u32 *)eld + i));
>  
>  	tmp = I915_READ(G4X_AUD_CNTL_ST);
>  	tmp |= eldv;
> @@ -466,7 +466,7 @@ static void hsw_audio_codec_enable(struct intel_encoder *encoder,
>  	/* Up to 84 bytes of hw ELD buffer */
>  	len = min(drm_eld_size(eld), 84);
>  	for (i = 0; i < len / 4; i++)
> -		I915_WRITE(HSW_AUD_EDID_DATA(pipe), *((u32 *)eld + i));
> +		I915_WRITE(HSW_AUD_EDID_DATA(pipe), *((const u32 *)eld + i));
>  
>  	/* ELD valid */
>  	tmp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
> @@ -534,7 +534,7 @@ static void ilk_audio_codec_enable(struct intel_encoder *encoder,
>  	struct drm_connector *connector = conn_state->connector;
>  	enum pipe pipe = crtc->pipe;
>  	enum port port = encoder->port;
> -	u8 *eld = connector->eld;
> +	const u8 *eld = connector->eld;
>  	u32 tmp, eldv;
>  	int len, i;
>  	i915_reg_t hdmiw_hdmiedid, aud_config, aud_cntl_st, aud_cntrl_st2;
> @@ -585,7 +585,7 @@ static void ilk_audio_codec_enable(struct intel_encoder *encoder,
>  	/* Up to 84 bytes of hw ELD buffer */
>  	len = min(drm_eld_size(eld), 84);
>  	for (i = 0; i < len / 4; i++)
> -		I915_WRITE(hdmiw_hdmiedid, *((u32 *)eld + i));
> +		I915_WRITE(hdmiw_hdmiedid, *((const u32 *)eld + i));
>  
>  	/* ELD valid */
>  	tmp = I915_READ(aud_cntrl_st2);
> -- 
> 2.11.0

-- 
Ville Syrjälä
Intel
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