Re: [PATCH] drm/i915/vlv: DP_SINK_COUNT is not reliable for valleyview platform.

From: Jani Nikula <jani.nikula@linux.intel.com>
To: Daniel Vetter <daniel@ffwll.ch>, Quanxian Wang <quanxian.wang@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915/vlv: DP_SINK_COUNT is not reliable for valleyview platform.
Date: Fri, 13 Jun 2014 12:12:00 +0300	[thread overview]
Message-ID: <87lht1xjfj.fsf@intel.com> (raw)
In-Reply-To: <20140613071629.GF5821@phenom.ffwll.local>

On Fri, 13 Jun 2014, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Fri, Jun 13, 2014 at 02:52:04PM +0800, Quanxian Wang wrote:
>> DP connector will be disconnected after chvt to another console
>> for 10 minutes or more on valleyview platform VTC1010.
>
> This needs _much_ more detail, really.
>
> Also it smells like we work around a sink issue, which means the correct
> quirk is to use some sink id (like OUI), _not_ the platform. Since this
> way you break all DP1.1+ stuff on vlv and if someone puts this panel onto
> a different platform it still doesn't work.

Furthermore you should end up in this code path *only* if you have a DP
branch device. This shouldn't happen for eDP or native DP
displays. Please confirm what kind of setup you're experiencing issues
with.

Frankly I wouldn't be surpised if we do have issues with branch devices,
but this is not the fix.

BR,
Jani.

>
> Or I completely don't understand this at all.
>
> Also, such a patch needs a full spec quote or a w/a citation or something
> solid if it's a more generic issue.
> -Daniel
>> 
>> Signed-off-by: Quanxian Wang <quanxian.wang@intel.com>
>> ---
>>  drivers/gpu/drm/i915/intel_dp.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>> index 2688f6d..0d127a5 100644
>> --- a/drivers/gpu/drm/i915/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/intel_dp.c
>> @@ -2942,6 +2942,7 @@ intel_dp_check_link_status(struct intel_dp *intel_dp)
>>  static enum drm_connector_status
>>  intel_dp_detect_dpcd(struct intel_dp *intel_dp)
>>  {
>> +	struct drm_device *dev = intel_dp_to_dev(intel_dp);
>>  	uint8_t *dpcd = intel_dp->dpcd;
>>  	uint8_t type;
>>  
>> @@ -2953,7 +2954,8 @@ intel_dp_detect_dpcd(struct intel_dp *intel_dp)
>>  		return connector_status_connected;
>>  
>>  	/* If we're HPD-aware, SINK_COUNT changes dynamically */
>> -	if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11 &&
>> +	if (!IS_VALLEYVIEW(dev) &&
>> +	    intel_dp->dpcd[DP_DPCD_REV] >= 0x11 &&
>>  	    intel_dp->downstream_ports[0] & DP_DS_PORT_HPD) {
>>  		uint8_t reg;
>>  		if (!intel_dp_aux_native_read_retry(intel_dp, DP_SINK_COUNT,
>> -- 
>> 1.8.1.2
>> 
>> _______________________________________________
>> Intel-gfx mailing list
>> Intel-gfx@lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Jani Nikula, Intel Open Source Technology Center