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

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

On Fri, 13 Jun 2014, "Wang, Quanxian" <quanxian.wang@intel.com> wrote:
>> -----Original Message-----
>> From: Daniel Vetter [mailto:daniel.vetter@ffwll.ch] On Behalf Of Daniel
>> Vetter
>> Sent: Friday, June 13, 2014 3:16 PM
>> To: Wang, Quanxian
>> Cc: intel-gfx@lists.freedesktop.org
>> Subject: Re: [Intel-gfx] [PATCH] drm/i915/vlv: DP_SINK_COUNT is not
>> reliable for valleyview platform.
>> 
>> 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.
> [Wang, Quanxian] Sorry, I am not sure what detail should be provided.
> The background is  in tizen-ivi, when Weston is running on vt1, and chvt to vt2, after 10 or more minutes, Weston will exit.
> After the investigation, I found in intel_dp_detect_dpcd function, it will use DP_SINK_COUNT to check if connector is connected or not.  KMS think it is not connected and return connector_status_disconnected, this will disable the DP connector. Weston will not get any disconnector, it will exit. That is the root cause. So I think use DP_SINK_COUNT is not reliable to check connector is connected or not.

Please see my other mail, and provide the info.

BR,
Jani.

>> 
>> 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.
> [Wang, Quanxian] Yes, it is a special issue happens on valleyview platform VTC1010. I just have only one type of valleyview platform vtc1010 and not sure if others vlv platform has the same issue which has dp1.1.
>> 
>> 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.
> [Wang, Quanxian] I am checking the related registers. Thanks.
>> -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
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-- 
Jani Nikula, Intel Open Source Technology Center