Re: [PATCH 2/2] drm/i915/dp: Restore the missing check for intel_dp_has_joiner

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 2/5/2026 6:23 PM, Imre Deak wrote:
> On Thu, Feb 05, 2026 at 06:07:44PM +0530, Nautiyal, Ankit K wrote:
>> On 2/5/2026 3:11 PM, Imre Deak wrote:
>>> On Thu, Feb 05, 2026 at 02:06:23PM +0530, Ankit Nautiyal wrote:
>>>> Commit ad121a62d566 ("drm/i915/dp: Rework pipe joiner logic in mode_valid")
>>>> replaced intel_dp_num_joined_pipes() with an explicit joiner candidate
>>>> iteration. The previous code implicitly checked for DP joiner capability
>>>> via intel_dp_has_joiner(), but this check was lost during the refactor.
>>>>
>>>> Restore the missing intel_dp_has_joiner() check in intel_dp_can_join() so
>>>> that DP specific joiner conditions are taken into account.
>>>>
>>>> This change also requires propagating struct intel_dp * from the callers
>>>> down to the new check.
>>>>
>>>> Fixes: ad121a62d566 ("drm/i915/dp: Rework pipe joiner logic in mode_valid")
>>>> Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
>>>> Cc: Imre Deak <imre.deak@intel.com>
>>>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
>>>> ---
>>>>    drivers/gpu/drm/i915/display/intel_dp.c     | 16 +++++++++++-----
>>>>    drivers/gpu/drm/i915/display/intel_dp.h     |  7 ++++---
>>>>    drivers/gpu/drm/i915/display/intel_dp_mst.c |  4 ++--
>>>>    3 files changed, 17 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
>>>> index 4f5b89f80e55..3021c64d0f85 100644
>>>> --- a/drivers/gpu/drm/i915/display/intel_dp.c
>>>> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>>>> @@ -1397,9 +1397,14 @@ bool intel_dp_has_dsc(const struct intel_connector *connector)
>>>>    }
>>>>    static
>>>> -bool intel_dp_can_join(struct intel_display *display,
>>>> +bool intel_dp_can_join(struct intel_dp *intel_dp,
>>>>    		       int num_joined_pipes)
>>>>    {
>>>> +	struct intel_display *display = to_intel_display(intel_dp);
>>>> +
>>>> +	if (num_joined_pipes > 1 && !intel_dp_has_joiner(intel_dp))
>>>> +		return false;
>>>> +
>>>>    	switch (num_joined_pipes) {
>>>>    	case 1:
>>>>    		return true;
>>>> @@ -1496,7 +1501,7 @@ intel_dp_mode_valid(struct drm_connector *_connector,
>>>>    	 * over candidate pipe counts and evaluate each combination.
>>>>    	 */
>>>>    	status = MODE_CLOCK_HIGH;
>>>> -	for_each_joiner_candidate(connector, mode, num_joined_pipes) {
>>>> +	for_each_joiner_candidate(intel_dp, connector, mode, num_joined_pipes) {
>>>>    		int dsc_slice_count = 0;
>>>>    		status = intel_pfit_mode_valid(display, mode, output_format, num_joined_pipes);
>>>> @@ -2895,7 +2900,7 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
>>>>    	    !intel_dp_supports_fec(intel_dp, connector, crtc_state))
>>>>    		return -EINVAL;
>>>> -	for_each_joiner_candidate(connector, adjusted_mode, num_joined_pipes) {
>>>> +	for_each_joiner_candidate(intel_dp, connector, adjusted_mode, num_joined_pipes) {
>>>>    		/*
>>>>    		 * NOTE:
>>>>    		 * The crtc_state->joiner_pipes should have been set at the end
>>>> @@ -7213,13 +7218,14 @@ int intel_dp_sdp_min_guardband(const struct intel_crtc_state *crtc_state,
>>>>    	return sdp_guardband;
>>>>    }
>>>> -bool intel_dp_joiner_candidate_valid(struct intel_connector *connector,
>>>> +bool intel_dp_joiner_candidate_valid(struct intel_dp *intel_dp,
>>>> +				     struct intel_connector *connector,
>>>>    				     int hdisplay,
>>>>    				     int num_joined_pipes)
>>> intel_dp can be always deducted from the connector, via
>>> intel_attached_dp(), so no need to pass intel_dp separately.
>> Since this function is called from the iterator macro for DP MST also, I was
>> wondering if for MST case we need to get it via encoder/dig_port.
> No, intel_attached_dp() works for MST connectors as well.

Oh ok, then I will just use intel_attached_dp().


Thanks & Regards,

Ankit

>
>> Regards,
>>
>> Ankit
>>
>>
>>>>    {
>>>>    	struct intel_display *display = to_intel_display(connector);
>>>> -	if (!intel_dp_can_join(display, num_joined_pipes))
>>>> +	if (!intel_dp_can_join(intel_dp, num_joined_pipes))
>>>>    		return false;
>>>>    	if (hdisplay > num_joined_pipes * intel_dp_max_hdisplay_per_pipe(display))
>>>> diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
>>>> index cbd7fcd3789f..37302ebe1cf9 100644
>>>> --- a/drivers/gpu/drm/i915/display/intel_dp.h
>>>> +++ b/drivers/gpu/drm/i915/display/intel_dp.h
>>>> @@ -227,12 +227,13 @@ bool intel_dp_dotclk_valid(struct intel_display *display,
>>>>    			   int htotal,
>>>>    			   int dsc_slice_count,
>>>>    			   int num_joined_pipes);
>>>> -bool intel_dp_joiner_candidate_valid(struct intel_connector *connector,
>>>> +bool intel_dp_joiner_candidate_valid(struct intel_dp *intel_dp,
>>>> +				     struct intel_connector *connector,
>>>>    				     int hdisplay,
>>>>    				     int num_joined_pipes);
>>>> -#define for_each_joiner_candidate(__connector, __mode, __num_joined_pipes) \
>>>> +#define for_each_joiner_candidate(__intel_dp, __connector, __mode, __num_joined_pipes) \
>>>>    	for ((__num_joined_pipes) = 1; (__num_joined_pipes) <= (I915_MAX_PIPES); (__num_joined_pipes)++) \
>>>> -		for_each_if(intel_dp_joiner_candidate_valid(__connector, (__mode)->hdisplay, __num_joined_pipes))
>>>> +		for_each_if(intel_dp_joiner_candidate_valid(__intel_dp, __connector, (__mode)->hdisplay, __num_joined_pipes))
>>>>    #endif /* __INTEL_DP_H__ */
>>>> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
>>>> index 29713075e413..b2d3f35edd78 100644
>>>> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
>>>> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
>>>> @@ -720,7 +720,7 @@ static int mst_stream_compute_config(struct intel_encoder *encoder,
>>>>    	pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
>>>>    	pipe_config->has_pch_encoder = false;
>>>> -	for_each_joiner_candidate(connector, adjusted_mode, num_joined_pipes) {
>>>> +	for_each_joiner_candidate(intel_dp, connector, adjusted_mode, num_joined_pipes) {
>>>>    		if (num_joined_pipes > 1)
>>>>    			pipe_config->joiner_pipes = GENMASK(crtc->pipe + num_joined_pipes - 1,
>>>>    							    crtc->pipe);
>>>> @@ -1524,7 +1524,7 @@ mst_connector_mode_valid_ctx(struct drm_connector *_connector,
>>>>    	}
>>>>    	*status = MODE_CLOCK_HIGH;
>>>> -	for_each_joiner_candidate(connector, mode, num_joined_pipes) {
>>>> +	for_each_joiner_candidate(intel_dp, connector, mode, num_joined_pipes) {
>>>>    		int dsc_slice_count = 0;
>>>>    		if (intel_dp_has_dsc(connector) &&
>>>> -- 
>>>> 2.45.2
>>>>