Re: [PATCH v3.1 1/3] drm/i915: Fix broken mst get_hw_state.

From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH v3.1 1/3] drm/i915: Fix broken mst get_hw_state.
Date: Thu, 6 Aug 2015 15:37:08 +0200	[thread overview]
Message-ID: <55C36304.6060305@linux.intel.com> (raw)
In-Reply-To: <20150806125924.GL17734@phenom.ffwll.local>

Op 06-08-15 om 14:59 schreef Daniel Vetter:
> On Thu, Aug 06, 2015 at 01:47:35PM +0200, Maarten Lankhorst wrote:
>> This function always returned false because intel_connector->encoder
>> is always NULL. Instead use the attached encoder from atomic.
> Note that you've broken this since you removed the updating of
> intel_connector->encoder somewhere in the 4.3 atomic series. So this is a
> regression fix. Can you please digg out the right commit?

Looks like 'Use full atomic modeset' broke it. intel_connector->encoder was updated in its set_config function..

Would below amend for this commit be good?

diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index ee2a77144373..671715ba8538 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -173,6 +173,11 @@ static void intel_mst_pre_enable_dp(struct intel_encoder *encoder)
 		return;
 	}
 
+	/* MST encoders are bound to a crtc, not to a connector,
+	 * force the mapping here for get_hw_state.
+	 */
+	found->encoder = encoder;
+
 	DRM_DEBUG_KMS("%d\n", intel_dp->active_mst_links);
 	intel_mst->port = found->port;
 

And corresponding amendment to the convert connector to atomic..

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a6617283b1bd..90caa62cf2c3 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6313,7 +6313,7 @@ static void intel_connector_check_state(struct intel_connector *connector)
 		I915_STATE_WARN(!crtc->state->active,
 		      "connector is active, but attached crtc isn't\n");
 
-		if (!encoder)
+		if (!encoder || encoder->type == INTEL_OUTPUT_DP_MST)
 			return;
 
 		I915_STATE_WARN(conn_state->best_encoder != encoder,

>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
>> ---
>>  drivers/gpu/drm/i915/intel_dp_mst.c | 7 +++++--
>>  1 file changed, 5 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
>> index e3a5864160fa..ff01569158ea 100644
>> --- a/drivers/gpu/drm/i915/intel_dp_mst.c
>> +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
>> @@ -395,9 +395,12 @@ static const struct drm_encoder_funcs intel_dp_mst_enc_funcs = {
>>  
>>  static bool intel_dp_mst_get_hw_state(struct intel_connector *connector)
>>  {
>> -	if (connector->encoder) {
>> +	struct intel_encoder *encoder;
>> +
>> +	encoder = to_intel_encoder(connector->base.state->best_encoder);
> Strictly speaking this won't work for hw state readout since what we
> really need to do is ask the mst connector which mst stream it accepts and
> then compare that with all the mst encoders ...
It's good enough to make sure the encoder callbacks did run.
> But that's been broken since forever. Only side-effect here is that
> fastboot won't work with mst and that's imo totally ok. Please also add
> this to your commit message.
HW readout runs before mst probing, so you wouldn't get the mst connectors anyway with fastboot. Not sure it needs a fixme. :-)
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