<div dir="ltr">I liked the approach and agree with Daniel, so with his suggestions feel free to use:<div>Reviewed-by: Rodrigo Vivi <<a href="mailto:rodrigo.vivi@intel.com">rodrigo.vivi@intel.com</a>> </div></div> <div class="gmail_quote"><div dir="ltr">On Fri, Sep 4, 2015 at 7:46 AM Daniel Vetter <<a href="mailto:daniel@ffwll.ch">daniel@ffwll.ch</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Fri, Sep 04, 2015 at 06:56:12PM +0530, Sonika Jindal wrote: > From: Shashank Sharma <<a href="mailto:shashank.sharma@intel.com" target="_blank">shashank.sharma@intel.com</a>> > > This patch adds a separate probe function for HDMI > EDID read over DDC channel. This function has been > registered as a .hot_plug handler for HDMI encoder. > > The current implementation of hdmi_detect() > function re-sets the cached HDMI edid (in connector->detect_edid) in > every detect call.This function gets called many times, sometimes > directly from userspace probes, forcing drivers to read EDID every > detect function call.This causes several problems like: > > 1. Race conditions in multiple hot_plug / unplug cases, between > interrupts bottom halves and userspace detections. > 2. Many Un-necessary EDID reads for single hotplug/unplug > 3. HDMI complaince failures which expects only one EDID read per hotplug > > This function will be serving the purpose of really reading the EDID > by really probing the DDC channel, and updating the cached EDID. > > The plan is to: > 1. i915 IRQ handler bottom half function already calls > intel_encoder->hotplug() function. Adding This probe function which > will read the EDID only in case of a hotplug / unplug. > 2. During init_connector his probe will be called to read the edid > 3. Reuse the cached EDID in hdmi_detect() function. > > The "< gen7" check is there because this was tested only for >=gen7 > platforms. For older platforms the hotplug/reading edid path remains same. > > v2: Calling set_edid instead of hdmi_probe during init. > Also, for platforms having DDI, intel_encoder for DP and HDMI is same > (taken from intel_dig_port), so for DP also, hot_plug function gets called > which is not intended here. So, check for HDMI in intel_hdmi_probe > Rely on HPD for updating edid only for platforms gen > 8 and also for VLV. > > v3: Dropping the gen < 8 || !VLV check. Now all platforms should rely on > hotplug or init for updating the edid.(Daniel) > Also, calling hdmi_probe in init instead of set_edid > > Signed-off-by: Shashank Sharma <<a href="mailto:shashank.sharma@intel.com" target="_blank">shashank.sharma@intel.com</a>> > Signed-off-by: Sonika Jindal <<a href="mailto:sonika.jindal@intel.com" target="_blank">sonika.jindal@intel.com</a>> > --- > drivers/gpu/drm/i915/intel_hdmi.c | 46 ++++++++++++++++++++++++++++++++----- > 1 file changed, 40 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c > index 5bdb386..1eda71a 100644 > --- a/drivers/gpu/drm/i915/intel_hdmi.c > +++ b/drivers/gpu/drm/i915/intel_hdmi.c > @@ -1368,23 +1368,53 @@ intel_hdmi_set_edid(struct drm_connector *connector) > return connected; > } > > +void intel_hdmi_probe(struct intel_encoder *intel_encoder) Please call it _hot_plug if it's for the _hot_plug path. > +{ > + struct intel_hdmi *intel_hdmi = > + enc_to_intel_hdmi(&intel_encoder->base); > + struct intel_connector *intel_connector = > + intel_hdmi->attached_connector; > + > + /* > + * We are here, means there is a hotplug or a force > + * detection. Clear the cached EDID and probe the > + * DDC bus to check the current status of HDMI. > + */ > + intel_hdmi_unset_edid(&intel_connector->base); > + if (intel_hdmi_set_edid(&intel_connector->base)) > + DRM_DEBUG_DRIVER("DDC probe: got EDID\n"); > + else > + DRM_DEBUG_DRIVER("DDC probe: no EDID\n"); > +} > + > static enum drm_connector_status > intel_hdmi_detect(struct drm_connector *connector, bool force) > { > enum drm_connector_status status; > + struct intel_connector *intel_connector = > + to_intel_connector(connector); > > DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", > connector-><a href="http://base.id" rel="noreferrer" target="_blank">base.id</a>, connector->name); > + /* > + * There are many userspace calls which probe EDID from > + * detect path. In case of multiple hotplug/unplug, these > + * can cause race conditions while probing EDID. Also its > + * waste of CPU cycles to read the EDID again and again > + * unless there is a real hotplug. > + * So, rely on hotplugs and init to read edid. > + * Check connector status based on availability of cached EDID. > + */ > > - intel_hdmi_unset_edid(connector); > - > - if (intel_hdmi_set_edid(connector)) { > + if (intel_connector->detect_edid) { > struct intel_hdmi *intel_hdmi = intel_attached_hdmi(connector); > - > - hdmi_to_dig_port(intel_hdmi)->base.type = INTEL_OUTPUT_HDMI; > status = connector_status_connected; > - } else > + hdmi_to_dig_port(intel_hdmi)->base.type = INTEL_OUTPUT_HDMI; > + DRM_DEBUG_DRIVER("hdmi status = connected\n"); > + } else { > status = connector_status_disconnected; > + DRM_DEBUG_DRIVER("hdmi status = disconnected\n"); > + } > > return status; > } > @@ -2104,11 +2134,15 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port, > intel_connector->unregister = intel_connector_unregister; > > intel_hdmi_add_properties(intel_hdmi, connector); > + intel_encoder->hot_plug = intel_hdmi_probe; > > intel_connector_attach_encoder(intel_connector, intel_encoder); > drm_connector_register(connector); > intel_hdmi->attached_connector = intel_connector; > > + /* Set edid during init */ > + intel_hdmi_probe(intel_encoder); Separate patch, but we really don't want this, initial probe should be done async to avoid stalling the driver. -Daniel > + > /* For G4X desktop chip, PEG_BAND_GAP_DATA 3:0 must first be written > * 0xd. Failure to do so will result in spurious interrupts being > * generated on the port when a cable is not attached. > -- > 1.7.10.4 > > _______________________________________________ > Intel-gfx mailing list > <a href="mailto:Intel-gfx@lists.freedesktop.org" target="_blank">Intel-gfx@lists.freedesktop.org</a> > <a href="http://lists.freedesktop.org/mailman/listinfo/intel-gfx" rel="noreferrer" target="_blank">http://lists.freedesktop.org/mailman/listinfo/intel-gfx</a> -- Daniel Vetter Software Engineer, Intel Corporation <a href="http://blog.ffwll.ch" rel="noreferrer" target="_blank">http://blog.ffwll.ch</a> _______________________________________________ Intel-gfx mailing list <a href="mailto:Intel-gfx@lists.freedesktop.org" target="_blank">Intel-gfx@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/intel-gfx" rel="noreferrer" target="_blank">http://lists.freedesktop.org/mailman/listinfo/intel-gfx</a> </blockquote></div>