Re: [Intel-gfx] [PATCH 2/2] drm/i915/dp: use opregion mailbox #5 EDID for eDP, if available

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

On Tue, 13 Oct 2020, "Lee, Shawn C" <shawn.c.lee@intel.com> wrote:
> On Mon, Oct 12, 2020 at 5:09 PM, Jani Nikula wrote:
>>On Mon, 12 Oct 2020, "Lee, Shawn C" <shawn.c.lee@intel.com> wrote:
>>> On Fri, Aug 28, 2020 at 06:19AM, Shankar Uma wrote:
>>>>> -----Original Message-----
>>>>> From: Jani Nikula <jani.nikula@intel.com>
>>>>> Sent: Friday, August 28, 2020 11:50 AM
>>>>> To: intel-gfx@lists.freedesktop.org
>>>>> Cc: Nikula, Jani <jani.nikula@intel.com>; Shankar, Uma
>>>>> <uma.shankar@intel.com>
>>>>> Subject: [PATCH 2/2] drm/i915/dp: use opregion mailbox #5 EDID for
>>>>> eDP, if available
>>>>>
>>>>> If a panel's EDID is broken, there may be an override EDID set in
>>>>> the ACPI OpRegion mailbox #5. Use it if available.
>>>>
>>>>Looks Good to me.
>>>>Reviewed-by: Uma Shankar <uma.shankar@intel.com>
>>>>
>>>>> Cc: Uma Shankar <uma.shankar@intel.com>
>>>>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>>>>> ---
>>>>>  drivers/gpu/drm/i915/display/intel_dp.c | 3 +++
>>>>>  1 file changed, 3 insertions(+)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
>>>>> b/drivers/gpu/drm/i915/display/intel_dp.c
>>>>> index c57ac83bf563..d1307be196a2 100644
>>>>> --- a/drivers/gpu/drm/i915/display/intel_dp.c
>>>>> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>>>>> @@ -8114,6 +8114,9 @@ static bool intel_edp_init_connector(struct
>>>>> intel_dp *intel_dp,  goto out_vdd_off;  }
>>>>>
>>>>> +/* Set up override EDID, if any, from ACPI OpRegion */
>>>>> +intel_opregion_edid_override(intel_connector);
>>>>> +
>>>
>>> Customer report DUT still get EDID from eDP panel instead of mailbox #5.
>>> After some investigations, this change can retrieve EDID from mailbox #5 properly.
>>> But driver still used panel's EDID to enable eDP display. This is
>>> because of drm_get_edid() was executed after
>>> intel_opregion_edid_override(). drm_get_edid() return panel's EDID and overwrite mailbox #5's.
>>
>>In recent kernels, drm_get_edid() respects EDID override, and calling
>>drm_get_edid() will return the override EDID from mailbox #5 instead of retrieving the actual EDID.
>>
>>Check the kernel version they're using and the drm_get_edid() implementation.
>>
>>BR,
>>Jani.
>>
>
> Just confirm customer is using kernel v5.8. Seems drm_edid.c already include
> the change for override_edid.
>
> BTW. override_edid should be "true" and used to over EDID in intel_opregion_edid_override() in patch 1. Right?
> But it is "false" in the patch 1.
>
> +connector->override_edid = false;
>


+
+	connector->override_edid = false;
+	ret = drm_connector_update_edid_property(connector, edid);
+	if (ret)
+		return;
+
+	connector->override_edid = true;
+	drm_dbg_kms(&i915->drm, "Using OpRegion EDID for [CONNECTOR:%d:%s]\n",
+		    connector->base.id, connector->name);


http://lore.kernel.org/r/20200831083657.15600-1-jani.nikula@intel.com

BR,
Jani.





> Best regards,
> Shawn
>
>>
>>>
>>> We try to move drm_get_edid() before intel_opregion_edid_override().
>>> The test result is positive, mailbox #5 EDID will substitute for panel's.
>>> It seems we may need some additional change for this patch. Thanks!
>>>
>>> Best regards,
>>> Shawn
>>>
>>>>>  mutex_lock(&dev->mode_config.mutex);
>>>>>  edid = drm_get_edid(connector, &intel_dp->aux.ddc);  if (edid) {
>>>>> --
>>>>> 2.20.1
>>
>>--
>>Jani Nikula, Intel Open Source Graphics Center
>>_______________________________________________
>>Intel-gfx mailing list
>>Intel-gfx@lists.freedesktop.org
>>https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Jani Nikula, Intel Open Source Graphics Center
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