Re: [PATCH] drm/i915: Unbreak check_digital_port_conflicts()

[Jani Nikula <jani.nikula@linux.intel.com>]

On Thu, 10 Dec 2015, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Mon, Dec 07, 2015 at 11:13:20PM +0200, ville.syrjala@linux.intel.com wrote:
>> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>> 
>> Atomic changes broke check_digital_port_conflicts(). It needs to look
>> at the global situation instead of just trying to find a conflict
>> within the current atomic state.
>> 
>> This bug made my HSW explode spectacularly after I had split the DDI
>> encoders into separate DP and HDMI encoders. With the fix, things
>> seem much more solid.
>> 
>> I hope holding the connection_mutex is enough protection that we can
>> actually walk the connectors even if they're not part of the current
>> atomic state...
>
> That is sufficient locking.
>> 
>> Cc: stable@vger.kernel.org
>
> Ugh. Long-term I think what we need is for all drivers (well at least
> atomic ones) to fill out the possible_clones stuff correctly in the
> encoder. And then check this in the atomic helpers. But that's way too
> much for -fixes.
>
> On the patch itself, for -fixes: Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Fails to apply in either fixes or dinq. Ville, please update.

BR,
Jani.


>
>> Cc: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
>> Fixes: 5448a00d3f06 ("drm/i915: Don't use staged config in check_digital_port_conflicts()")
>> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
>> ---
>>  drivers/gpu/drm/i915/intel_display.c | 13 +++++++++----
>>  1 file changed, 9 insertions(+), 4 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>> index 1c6d56c84b9d..c902964ceca0 100644
>> --- a/drivers/gpu/drm/i915/intel_display.c
>> +++ b/drivers/gpu/drm/i915/intel_display.c
>> @@ -12253,18 +12253,23 @@ static void intel_dump_pipe_config(struct intel_crtc *crtc,
>>  
>>  static bool check_digital_port_conflicts(struct drm_atomic_state *state)
>>  {
>> -	struct intel_encoder *encoder;
>> +	struct drm_device *dev = state->dev;
>>  	struct drm_connector *connector;
>> -	struct drm_connector_state *connector_state;
>>  	unsigned int used_ports = 0;
>> -	int i;
>>  
>>  	/*
>>  	 * Walk the connector list instead of the encoder
>>  	 * list to detect the problem on ddi platforms
>>  	 * where there's just one encoder per digital port.
>>  	 */
>> -	for_each_connector_in_state(state, connector, connector_state, i) {
>> +	drm_for_each_connector(connector, dev) {
>> +		struct drm_connector_state *connector_state;
>> +		struct intel_encoder *encoder;
>> +
>> +		connector_state = drm_atomic_get_existing_connector_state(state, connector);
>> +		if (!connector_state)
>> +			connector_state = connector->state;
>> +
>>  		if (!connector_state->best_encoder)
>>  			continue;
>>  
>> -- 
>> 2.4.10
>> 
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-- 
Jani Nikula, Intel Open Source Technology Center
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