Re: [PATCH] drm/i915: revert intel_dp_probe_oui call during HPD interrupt handler

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

On Fri, 06 Jun 2014, Clint Taylor <clinton.a.taylor@intel.com> wrote:
> On 06/06/2014 02:41 AM, Jani Nikula wrote:
>> On Thu, 05 Jun 2014, Daniel Vetter <daniel@ffwll.ch> wrote:
>>> On Wed, Jun 04, 2014 at 03:29:41PM -0700, clinton.a.taylor@intel.com wrote:
>>>> From: Clint Taylor <clinton.a.taylor@intel.com>
>>>>
>>>> Remove OUI read function from the lower half interrupt handler. Upon
>>>> closing the eDP panel lid an HPD interrupt is generated. The lower half
>>>> handler calls intel_dp_probe_oui() as part of intel_dp_detect().
>>>> intel_dp_probe_oui() enables eDP VDD and subsequently disables eDP VDD
>>>> causing another HPD interrupt. This cycle repeats every 3.6 seconds with
>>>> VDD asserted for 3.5 of those seconds until the lid is opened again.
>>>>
>>>> Revert of 0d198328538276c4459ef5de081e68ae60e6c4c2
>>>> Revert of 351cfc34db8decb0c5cc1aac7cf1780a0e45c8b1
>>>>
>>>> Signed-off-by: Clint Taylor <clinton.a.taylor@intel.com>
>>>
>>> Hm, this is funky ... we currently don't handle port A hotplug events, and
>>> we filter hotplug events properly.
>>>
>>> How does this exactly blow up for you? Or is this port D?
>>>
>>> We might want to have some filtering here checking whether the edp panel
>>> is on or off. Also the delayed work is _way_ too long.
>>
>> Dave just posted a patch that depends on the OUI [1].
>
> I didn't see any changes to intel_dp_probe_oui() in Dave's patches. The 
> function is still a NOP as it doesn't save the OUI reads.

See the referenced "drm/i915/dp: add support for load detect Apple
DP->VGA dongles" patch, it adds more logic to the end of
intel_dp_probe_oui(). I'm not talking about the MST series.

BR,
Jani.


>
> I'm also concerned about his intel_dp_probe_mst() as it also turns on 
> and off eDP VDD to read the DPCD registers. In the intel_dp_detect() 
> function of his patches he is now calling intel_dp_probe_oui() then 
> immediately calls intel_dp_probe_mst() resulting in the panel being 
> turned on and off twice.
>
> Clint
>
>>
>> BR,
>> Jani.
>>
>>
>> [1] http://mid.gmane.org/1402023404-22324-1-git-send-email-airlied@gmail.com
>>
>>
>>
>>
>>
>>> -Daniel
>>>
>>>> ---
>>>>   drivers/gpu/drm/i915/intel_dp.c |   23 -----------------------
>>>>   1 file changed, 23 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>>>> index 2a00cb8..246d2c1 100644
>>>> --- a/drivers/gpu/drm/i915/intel_dp.c
>>>> +++ b/drivers/gpu/drm/i915/intel_dp.c
>>>> @@ -2867,27 +2867,6 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
>>>>   	return true;
>>>>   }
>>>>
>>>> -static void
>>>> -intel_dp_probe_oui(struct intel_dp *intel_dp)
>>>> -{
>>>> -	u8 buf[3];
>>>> -
>>>> -	if (!(intel_dp->dpcd[DP_DOWN_STREAM_PORT_COUNT] & DP_OUI_SUPPORT))
>>>> -		return;
>>>> -
>>>> -	intel_edp_panel_vdd_on(intel_dp);
>>>> -
>>>> -	if (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_SINK_OUI, buf, 3) == 3)
>>>> -		DRM_DEBUG_KMS("Sink OUI: %02hx%02hx%02hx\n",
>>>> -			      buf[0], buf[1], buf[2]);
>>>> -
>>>> -	if (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_BRANCH_OUI, buf, 3) == 3)
>>>> -		DRM_DEBUG_KMS("Branch OUI: %02hx%02hx%02hx\n",
>>>> -			      buf[0], buf[1], buf[2]);
>>>> -
>>>> -	edp_panel_vdd_off(intel_dp, false);
>>>> -}
>>>> -
>>>>   int intel_dp_sink_crc(struct intel_dp *intel_dp, u8 *crc)
>>>>   {
>>>>   	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
>>>> @@ -3178,8 +3157,6 @@ intel_dp_detect(struct drm_connector *connector, bool force)
>>>>   	if (status != connector_status_connected)
>>>>   		goto out;
>>>>
>>>> -	intel_dp_probe_oui(intel_dp);
>>>> -
>>>>   	if (intel_dp->force_audio != HDMI_AUDIO_AUTO) {
>>>>   		intel_dp->has_audio = (intel_dp->force_audio == HDMI_AUDIO_ON);
>>>>   	} else {
>>>> --
>>>> 1.7.9.5
>>>>
>>>> _______________________________________________
>>>> 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