On Thu, Mar 17, 2016 at 09:15:39PM +0530, Sharma, Shashank wrote:
> Regards
> Shashank
>
> On 3/17/2016 6:34 PM, Ville Syrjälä wrote:
> >On Thu, Mar 17, 2016 at 01:29:25PM +0530, Shashank Sharma wrote:
> >>This patch restricts usage of live status check for HDMI detection.
> >>While testing certain (monitor + cable) combinations with various
> >>intel platforms, it seems that live status register is not reliable
> >>on some older devices. So limit the live_status check from VLV onwards.
> >>
> >>This fixes a regression introduced in:
> >> commit: 237ed86 "drm/i915: Check live status"
> >> Author: Sonika Jindal <sonika.jindal@xxxxxxxxx>
> >> Date: Tue Sep 15 09:44:20 2015 +0530
> >>
> >>Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxxxx>
> >>---
> >> drivers/gpu/drm/i915/intel_hdmi.c | 22 ++++++++++++++--------
> >> 1 file changed, 14 insertions(+), 8 deletions(-)
> >>
> >>diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> >>index e2dab48..d24d18a 100644
> >>--- a/drivers/gpu/drm/i915/intel_hdmi.c
> >>+++ b/drivers/gpu/drm/i915/intel_hdmi.c
> >>@@ -1397,7 +1397,8 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
> >> enum drm_connector_status status;
> >> struct intel_hdmi *intel_hdmi = intel_attached_hdmi(connector);
> >> struct drm_i915_private *dev_priv = to_i915(connector->dev);
> >>- bool live_status = false;
> >>+ struct drm_device *dev = connector->dev;
> >>+ bool live_status = true;
> >> unsigned int try;
> >>
> >> DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
> >>@@ -1405,16 +1406,21 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
> >>
> >> intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
> >>
> >>- for (try = 0; !live_status && try < 9; try++) {
> >>- if (try)
> >>- msleep(10);
> >>- live_status = intel_digital_port_connected(dev_priv,
> >>+ /*
> >>+ * Live status check for HDMI detection is not very
> >>+ * reliable on older platforms. So insist the live
> >>+ * status check for EDID read from VLV onwards.
> >>+ */
> >>+ if (INTEL_INFO(dev)->gen >= 7 && !IS_IVYBRIDGE(dev)) {
> >>+ for (try = 0; !live_status && try < 9; try++) {
> >>+ if (try)
> >>+ msleep(10);
> >>+ live_status = intel_digital_port_connected(dev_priv,
> >> hdmi_to_dig_port(intel_hdmi));
> >>+ }
> >>+ DRM_DEBUG_KMS("Live status %s\n", live_status ? "up" : "down");
> >> }
> >>
> >>- if (!live_status)
> >>- DRM_DEBUG_KMS("Live status not up!");
> >>-
> >
> >As I said before, I think this whole thing could be solved with a simple
> >two-liner here:
> >
> >+ if (...)
> >+ live_status = true;
> >
> Yes I remember, and I replied on that already that why we would like
> to keep the live status check. In fact I would be ok to remove this
> check if you can suggest some other way of making this work for
> other operating systems/sw platforms.
The question is what is the safest approach for stable@ and for that
just doing as we historically did and ignore live_status makes the most
sense. Once the regressions have been rectified, then you can decide how
best to approach -next.
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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