linux-kernel - Re: [PATCH v2 5/8] drm: Use new mode_valid() helpers in connector probe helper

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Message-ID: <a6bf48e3-7c90-90c2-a321-703943474424@synopsys.com>
Date:   Wed, 10 May 2017 09:59:51 +0100
From:   Jose Abreu <Jose.Abreu@...opsys.com>
To:     Daniel Vetter <daniel.vetter@...ll.ch>
CC:     Jose Abreu <Jose.Abreu@...opsys.com>,
        <dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>,
        Carlos Palminha <CARLOS.PALMINHA@...opsys.com>,
        Alexey Brodkin <Alexey.Brodkin@...opsys.com>,
        Ville Syrjälä <ville.syrjala@...ux.intel.com>,
        Dave Airlie <airlied@...ux.ie>,
        Andrzej Hajda <a.hajda@...sung.com>,
        Archit Taneja <architt@...eaurora.org>
Subject: Re: [PATCH v2 5/8] drm: Use new mode_valid() helpers in connector
 probe helper

Hi Daniel,


On 10-05-2017 09:01, Daniel Vetter wrote:
> On Tue, May 09, 2017 at 06:00:12PM +0100, Jose Abreu wrote:
>> This changes the connector probe helper function to use the new
>> encoder->mode_valid() and crtc->mode_valid() helper callbacks to
>> validate the modes.
>>
>> The new callbacks are optional so the behaviour remains the same
>> if they are not implemented. If they are, then the code loops
>> through all the connector's encodersXcrtcs and calls the
>> callback.
>>
>> If at least a valid encoderXcrtc combination is found which
>> accepts the mode then the function returns MODE_OK.
>>
>> Signed-off-by: Jose Abreu <joabreu@...opsys.com>
>> Cc: Carlos Palminha <palminha@...opsys.com>
>> Cc: Alexey Brodkin <abrodkin@...opsys.com>
>> Cc: Ville Syrjälä <ville.syrjala@...ux.intel.com>
>> Cc: Daniel Vetter <daniel.vetter@...ll.ch>
>> Cc: Dave Airlie <airlied@...ux.ie>
>> Cc: Andrzej Hajda <a.hajda@...sung.com>
>> Cc: Archit Taneja <architt@...eaurora.org>
>> ---
>>
>> Changes v1->v2:
>> 	- Use new helpers suggested by Ville
>> 	- Change documentation (Daniel)
>>
>>  drivers/gpu/drm/drm_probe_helper.c | 60 ++++++++++++++++++++++++++++++++++++--
>>  1 file changed, 57 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
>> index 1b0c14a..de47413 100644
>> --- a/drivers/gpu/drm/drm_probe_helper.c
>> +++ b/drivers/gpu/drm/drm_probe_helper.c
>> @@ -39,6 +39,8 @@
>>  #include <drm/drm_fb_helper.h>
>>  #include <drm/drm_edid.h>
>>  
>> +#include "drm_crtc_internal.h"
>> +
>>  /**
>>   * DOC: output probing helper overview
>>   *
>> @@ -80,6 +82,54 @@
>>  	return MODE_OK;
>>  }
>>  
>> +static enum drm_mode_status
>> +drm_mode_validate_connector(struct drm_connector *connector,
>> +			    struct drm_display_mode *mode)
>> +{
>> +	struct drm_device *dev = connector->dev;
>> +	uint32_t *ids = connector->encoder_ids;
>> +	enum drm_mode_status ret = MODE_OK;
>> +	unsigned int i;
>> +
>> +	/* Step 1: Validate against connector */
>> +	ret = drm_connector_mode_valid(connector, mode);
>> +	if (ret != MODE_OK)
>> +		return ret;
>> +
>> +	/* Step 2: Validate against encoders and crtcs */
>> +	for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
>> +		struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
>> +		struct drm_crtc *crtc;
>> +
>> +		if (!encoder)
>> +			continue;
>> +
>> +		ret = drm_encoder_mode_valid(encoder, mode);
>> +		if (ret != MODE_OK) {
>> +			/* No point in continuing for crtc check as this encoder
>> +			 * will not accept the mode anyway. If all encoders
>> +			 * reject the mode then, at exit, ret will not be
>> +			 * MODE_OK. */
>> +			continue;
>> +		}
> One thing I've forgotten the last time around: Please also check
> bridge->mode_valid here. The encoder->bridge mapping is fixed.

Ok, will add in next version.

Best regards,
Jose Miguel Abreu

>
> Otherwise I think this looks good.
> -Daniel
>
>> +
>> +		drm_for_each_crtc(crtc, dev) {
>> +			if (!drm_encoder_crtc_ok(encoder, crtc))
>> +				continue;
>> +
>> +			ret = drm_crtc_mode_valid(crtc, mode);
>> +			if (ret == MODE_OK) {
>> +				/* If we get to this point there is at least
>> +				 * one combination of encoder+crtc that works
>> +				 * for this mode. Lets return now. */
>> +				return ret;
>> +			}
>> +		}
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>>  static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
>>  {
>>  	struct drm_cmdline_mode *cmdline_mode;
>> @@ -284,7 +334,11 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
>>   *    - drm_mode_validate_flag() checks the modes against basic connector
>>   *      capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
>>   *    - the optional &drm_connector_helper_funcs.mode_valid helper can perform
>> - *      driver and/or hardware specific checks
>> + *      driver and/or sink specific checks
>> + *    - the optional &drm_crtc_helper_funcs.mode_valid and
>> + *      &drm_encoder_helper_funcs.mode_valid helpers can perform driver and/or
>> + *      source specific checks which are also enforced by the modeset/atomic
>> + *      helpers
>>   *
>>   * 5. Any mode whose status is not OK is pruned from the connector's modes list,
>>   *    accompanied by a debug message indicating the reason for the mode's
>> @@ -428,8 +482,8 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
>>  		if (mode->status == MODE_OK)
>>  			mode->status = drm_mode_validate_flag(mode, mode_flags);
>>  
>> -		if (mode->status == MODE_OK && connector_funcs->mode_valid)
>> -			mode->status = connector_funcs->mode_valid(connector,
>> +		if (mode->status == MODE_OK)
>> +			mode->status = drm_mode_validate_connector(connector,
>>  								   mode);
>>  	}
>>  
>> -- 
>> 1.9.1
>>
>>