linux-kernel - Re: [PATCH] drm/stm: ltdc: fix deferred endpoint management

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Message-ID: <d2194303-8b95-09f8-0623-d29b9769bd50@st.com>
Date:   Fri, 27 Apr 2018 12:59:25 +0000
From:   Philippe CORNU <philippe.cornu@...com>
To:     Yannick FERTRE <yannick.fertre@...com>,
        Benjamin Gaignard <benjamin.gaignard@...aro.org>,
        Vincent ABRIOU <vincent.abriou@...com>,
        "David Airlie" <airlied@...ux.ie>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Alexandre TORGUE <alexandre.torgue@...com>
Subject: Re: [PATCH] drm/stm: ltdc: fix deferred endpoint management


On 04/25/2018 09:12 AM, Yannick FERTRE wrote:
> Hi Philippe,
> 
> Reviewed-by: Yannick Fertré <yannick.fertre@...com>

Applied on drm-misc-next.
Many thanks,
Philippe :-)


> 
> 
> On 04/17/2018 01:34 PM, Philippe Cornu wrote:
>> When a driver related to one of the endpoints is deferred
>> due to probe dependencies (i2c, spi...) but the other one
>> is ready, ltdc probe continues and the deferred driver
>> will never be probed again.
>>
>> The fix consists in waiting for all deferred endpoints before
>> continuing the ltdc probe.
>>
>> Signed-off-by: Philippe Cornu <philippe.cornu@...com>
>> ---
>>    drivers/gpu/drm/stm/ltdc.c | 11 +++++------
>>    1 file changed, 5 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
>> index e3121d9e4230..014cef8cef37 100644
>> --- a/drivers/gpu/drm/stm/ltdc.c
>> +++ b/drivers/gpu/drm/stm/ltdc.c
>> @@ -987,14 +987,13 @@ int ltdc_load(struct drm_device *ddev)
>>    						  &bridge[i]);
>>    
>>    		/*
>> -		 * If at least one endpoint is ready, continue probing,
>> -		 * else if at least one endpoint is -EPROBE_DEFER and
>> -		 * there is no previous ready endpoints, defer probing.
>> +		 * If at least one endpoint is -EPROBE_DEFER, defer probing,
>> +		 * else if at least one endpoint is ready, continue probing.
>>    		 */
>> -		if (!ret)
>> +		if (ret == -EPROBE_DEFER)
>> +			return ret;
>> +		else if (!ret)
>>    			endpoint_not_ready = 0;
>> -		else if (ret == -EPROBE_DEFER && endpoint_not_ready)
>> -			endpoint_not_ready = -EPROBE_DEFER;
>>    	}
>>    
>>    	if (endpoint_not_ready)