Re: [PATCH v2 1/2] drm/probe-helper: Add helper for drm_helper_probe_single_connector_modes()

[Thomas Zimmermann <tzimmermann@suse.de>]

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Hi

Am 10.05.22 um 22:13 schrieb Douglas Anderson:
> The drm_helper_probe_single_connector_modes() is a bit long. Let's
> break a chunk off to update and validate modes. This helps avoid one
> goto and also will allow us to more easily call the helper a second
> time in a future patch without adding looping or another goto.
> 
> This change is intended to be a no-op change--just code movement.
> 
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
> ---
> 
> Changes in v2:
> - Two underscores for __drm_helper_update_and_validate().
> - Return err and use WARN_ON instead of returning a bool.
> 
>   drivers/gpu/drm/drm_probe_helper.c | 107 ++++++++++++++++-------------
>   1 file changed, 61 insertions(+), 46 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> index 682359512996..ff3dd9a5da70 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -354,6 +354,61 @@ drm_helper_probe_detect(struct drm_connector *connector,
>   }
>   EXPORT_SYMBOL(drm_helper_probe_detect);
>   
> +static int __drm_helper_update_and_validate(struct drm_connector *connector,
> +					    uint32_t maxX, uint32_t maxY,
> +					    struct drm_modeset_acquire_ctx *ctx)
> +{
> +	struct drm_device *dev = connector->dev;
> +	struct drm_display_mode *mode;
> +	int mode_flags = 0;
> +	int ret;
> +
> +	drm_connector_list_update(connector);
> +
> +	if (connector->interlace_allowed)
> +		mode_flags |= DRM_MODE_FLAG_INTERLACE;
> +	if (connector->doublescan_allowed)
> +		mode_flags |= DRM_MODE_FLAG_DBLSCAN;
> +	if (connector->stereo_allowed)
> +		mode_flags |= DRM_MODE_FLAG_3D_MASK;
> +
> +	list_for_each_entry(mode, &connector->modes, head) {
> +		if (mode->status != MODE_OK)
> +			continue;
> +
> +		mode->status = drm_mode_validate_driver(dev, mode);
> +		if (mode->status != MODE_OK)
> +			continue;
> +
> +		mode->status = drm_mode_validate_size(mode, maxX, maxY);
> +		if (mode->status != MODE_OK)
> +			continue;
> +
> +		mode->status = drm_mode_validate_flag(mode, mode_flags);
> +		if (mode->status != MODE_OK)
> +			continue;
> +
> +		ret = drm_mode_validate_pipeline(mode, connector, ctx,
> +						 &mode->status);
> +		if (ret) {
> +			drm_dbg_kms(dev,
> +				    "drm_mode_validate_pipeline failed: %d\n",
> +				    ret);
> +
> +			if (drm_WARN_ON_ONCE(dev, ret != -EDEADLK))
> +				mode->status = MODE_ERROR;
> +			else
> +				return -EDEADLK;
> +		}
> +
> +		if (mode->status != MODE_OK)
> +			continue;
> +		mode->status = drm_mode_validate_ycbcr420(mode, connector);
> +	}
> +
> +	return 0;
> +}
> +
>   /**
>    * drm_helper_probe_single_connector_modes - get complete set of display modes
>    * @connector: connector to probe
> @@ -421,7 +476,6 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
>   	const struct drm_connector_helper_funcs *connector_funcs =
>   		connector->helper_private;
>   	int count = 0, ret;
> -	int mode_flags = 0;
>   	bool verbose_prune = true;
>   	enum drm_connector_status old_status;
>   	struct drm_modeset_acquire_ctx ctx;
> @@ -519,52 +573,13 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
>   			   connector->status == connector_status_unknown))
>   		count = drm_add_modes_noedid(connector, 1024, 768);
>   	count += drm_helper_probe_add_cmdline_mode(connector);
> -	if (count == 0)
> -		goto prune;
> -
> -	drm_connector_list_update(connector);
> -
> -	if (connector->interlace_allowed)
> -		mode_flags |= DRM_MODE_FLAG_INTERLACE;
> -	if (connector->doublescan_allowed)
> -		mode_flags |= DRM_MODE_FLAG_DBLSCAN;
> -	if (connector->stereo_allowed)
> -		mode_flags |= DRM_MODE_FLAG_3D_MASK;
> -
> -	list_for_each_entry(mode, &connector->modes, head) {
> -		if (mode->status != MODE_OK)
> -			continue;
> -
> -		mode->status = drm_mode_validate_driver(dev, mode);
> -		if (mode->status != MODE_OK)
> -			continue;
> -
> -		mode->status = drm_mode_validate_size(mode, maxX, maxY);
> -		if (mode->status != MODE_OK)
> -			continue;
> -
> -		mode->status = drm_mode_validate_flag(mode, mode_flags);
> -		if (mode->status != MODE_OK)
> -			continue;
> -
> -		ret = drm_mode_validate_pipeline(mode, connector, &ctx,
> -						 &mode->status);
> -		if (ret) {
> -			drm_dbg_kms(dev,
> -				    "drm_mode_validate_pipeline failed: %d\n",
> -				    ret);
> -
> -			if (drm_WARN_ON_ONCE(dev, ret != -EDEADLK)) {
> -				mode->status = MODE_ERROR;
> -			} else {
> -				drm_modeset_backoff(&ctx);
> -				goto retry;
> -			}
> +	if (count != 0) {
> +		ret = __drm_helper_update_and_validate(connector, maxX, maxY, &ctx);
> +		if (ret == -EDEADLK) {
> +			drm_modeset_backoff(&ctx);
> +			goto retry;
>   		}
> -
> -		if (mode->status != MODE_OK)
> -			continue;
> -		mode->status = drm_mode_validate_ycbcr420(mode, connector);
> +		WARN_ON(ret);

One more thing. AFAICT you already warned in 
__drm_helper_update_and_validate() about the error, so this WARN_ON 
should be removed.

With that change:

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>

Best regards
Thomas


>   	}
>   
>   prune:

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

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