[Intel-gfx] [PATCH 3/5] drm/i915: Update CRTC state if connector link status property changed

[Maarten Lankhorst]

Op 18-11-16 om 15:11 schreef Ville Syrjälä:
> On Fri, Nov 18, 2016 at 02:50:52PM +0100, Maarten Lankhorst wrote:
>> Op 18-11-16 om 08:13 schreef Manasi Navare:
>>> CRTC state connector_changed needs to be set to true
>>> if connector link status property has changed. This will tell the
>>> driver to do a complete modeset due to change in connector property.
>>>
>>> Acked-by: Harry Wentland <harry.wentland at amd.com>
>>> Acked-by: Tony Cheng <tony.cheng at amd.com>
>>> Cc: dri-devel at lists.freedesktop.org
>>> Cc: Jani Nikula <jani.nikula at linux.intel.com>
>>> Cc: Daniel Vetter <daniel.vetter at intel.com>
>>> Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
>>> Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
>>> ---
>>>  drivers/gpu/drm/drm_atomic_helper.c | 7 +++++++
>>>  1 file changed, 7 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
>>> index 0b16587..2125fd1 100644
>>> --- a/drivers/gpu/drm/drm_atomic_helper.c
>>> +++ b/drivers/gpu/drm/drm_atomic_helper.c
>>> @@ -519,6 +519,13 @@ static int handle_conflicting_encoders(struct drm_atomic_state *state,
>>>  					       connector_state);
>>>  		if (ret)
>>>  			return ret;
>>> +
>>> +		if (connector->state->crtc) {
>>> +			crtc_state = drm_atomic_get_existing_crtc_state(state,
>>> +									connector->state->crtc);
>>> +			if (connector->link_status == DRM_MODE_LINK_STATUS_BAD)
>>> +				crtc_state->connectors_changed = true;
>>> +		}
>>>  	}
>>>  
>>>  	/*
>> This will cause ordinary atomic commits that happen to change connector flags to potentially fail with -EINVAL if ALLOW_MODESET is not set.
>> For this reason I'm not sure this flag should be set automatically by the kernel. Could we add add a retrain link property instead, that
>> always return 0 when queried, but writing a 1 causing connectors_changed to be set on bad link status?
> Or just check for allow_modeset before setting connectors_changed=true here?

I don't think modesets should be done automatically like that, even if ALLOW_MODESET is set a modeset may not be expected by userspace.