Re: [PATCH v3 2/3] drm/msm/dpu: handle failures while initializing displays

From: Jeykumar Sankaran <jsanka-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
To: Sean Paul <sean-p7yTbzM4H96eqtR555YLDQ@public.gmane.org>
Cc: linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	robdclark-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
	dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org,
	jcrouse-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org,
	seanpaul-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org,
	hoegsberg-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org,
	freedreno-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
Subject: Re: [PATCH v3 2/3] drm/msm/dpu: handle failures while initializing displays
Date: Mon, 17 Dec 2018 11:35:22 -0800	[thread overview]
Message-ID: <0e9003608254bfe2529468e349c70cff@codeaurora.org> (raw)
In-Reply-To: <20181214152209.GQ154160@art_vandelay>

On 2018-12-14 07:22, Sean Paul wrote:
> On Thu, Dec 13, 2018 at 10:51:03AM -0800, Jeykumar Sankaran wrote:
>> Bail out KMS hw init on display initialization failures with
>> proper error logging.
>> 
>> changes in v3:
>> 	- introduced in the series
>> 
>> Signed-off-by: Jeykumar Sankaran <jsanka@codeaurora.org>
>> ---
>>  drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 39
> +++++++++++++++++++++++----------
>>  1 file changed, 27 insertions(+), 12 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>> index 685686e..39c8549 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>> @@ -405,33 +405,36 @@ static void dpu_kms_wait_for_commit_done(struct
> msm_kms *kms,
>>  	}
>>  }
>> 
>> -static void _dpu_kms_initialize_dsi(struct drm_device *dev,
>> +static int _dpu_kms_initialize_dsi(struct drm_device *dev,
>>  				    struct msm_drm_private *priv,
>>  				    struct dpu_kms *dpu_kms)
>>  {
>>  	struct drm_encoder *encoder = NULL;
>> -	int i, rc;
>> +	int i, rc = 0;
>> +
>> +	if (!(priv->dsi[0] || priv->dsi[1]))
> 
> It'd be nice to not have to support both blocks if only one is hooked 
> up.
> Perhaps move the TODO below above this check.
> 
For dual DSI panels (e.g: MTP panels), both of these blocks will be 
populated.
TODO comment below is to convey that the support for two independent 
single DSI
panels is not yet available in DPU.

Thanks and Regards,
Jeykumar S.
>> +		return rc;
>> 
>>  	/*TODO: Support two independent DSI connectors */
>>  	encoder = dpu_encoder_init(dev, DRM_MODE_ENCODER_DSI);
>> -	if (IS_ERR_OR_NULL(encoder)) {
>> +	if (IS_ERR(encoder)) {
>>  		DPU_ERROR("encoder init failed for dsi display\n");
>> -		return;
>> +		return PTR_ERR(encoder);
>>  	}
>> 
>>  	for (i = 0; i < ARRAY_SIZE(priv->dsi); i++) {
>> -		if (!priv->dsi[i]) {
>> -			DPU_DEBUG("invalid msm_dsi for ctrl %d\n", i);
>> -			return;
>> -		}
>> +		if (!priv->dsi[i])
> 
> I don't think this is possible given the check at the beginning of the
> function
> 
>> +			continue;
>> 
>>  		rc = msm_dsi_modeset_init(priv->dsi[i], dev, encoder);
>>  		if (rc) {
>>  			DPU_ERROR("modeset_init failed for dsi[%d], rc =
> %d\n",
>>  				i, rc);
>> -			continue;
>> +			return rc;
>>  		}
>>  	}
>> +
>> +	return rc;
> 
> nit: You can keep rc uninitialized above and just return 0 here.
> 
>>  }
>> 
>>  /**
>> @@ -442,16 +445,24 @@ static void _dpu_kms_initialize_dsi(struct
> drm_device *dev,
>>   * @dpu_kms:    Pointer to dpu kms structure
>>   * Returns:     Zero on success
>>   */
>> -static void _dpu_kms_setup_displays(struct drm_device *dev,
>> +static int _dpu_kms_setup_displays(struct drm_device *dev,
>>  				    struct msm_drm_private *priv,
>>  				    struct dpu_kms *dpu_kms)
>>  {
>> -	_dpu_kms_initialize_dsi(dev, priv, dpu_kms);
>> +	int rc = 0;
> 
> nit: No need to initialize to 0
> 
>> +
>> +	rc = _dpu_kms_initialize_dsi(dev, priv, dpu_kms);
>> +	if (rc) {
>> +		DPU_ERROR("failed to initialize dsi, rc = %d\n", rc);
>> +		return rc;
>> +	}
>> 
>>  	/**
>>  	 * Extend this function to initialize other
>>  	 * types of displays
>>  	 */
>> +
>> +	return rc;
>>  }
>> 
>>  static void _dpu_kms_drm_obj_destroy(struct dpu_kms *dpu_kms)
>> @@ -517,7 +528,11 @@ static int _dpu_kms_drm_obj_init(struct dpu_kms
> *dpu_kms)
>>  	 * Create encoder and query display drivers to create
>>  	 * bridges and connectors
>>  	 */
>> -	_dpu_kms_setup_displays(dev, priv, dpu_kms);
>> +	ret = _dpu_kms_setup_displays(dev, priv, dpu_kms);
>> +	if (ret) {
>> +		DPU_ERROR("failed to setup display, rc = %d\n", ret);
>> +		goto fail;
>> +	}
>> 
>>  	max_crtc_count = min(catalog->mixer_count,
>>  			     (u32)dev->mode_config.num_encoder);
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
> Forum,
>> a Linux Foundation Collaborative Project
>> 
>> _______________________________________________
>> Freedreno mailing list
>> Freedreno@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/freedreno

-- 
Jeykumar S
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