On 9/2/2015 2:43 PM, Daniel Vetter wrote:
On Thu, Aug 27, 2015 at 02:18:32PM +0530, Sivakumar Thulasimani wrote:
From: "Thulasimani,Sivakumar" <sivakumar.thulasimani@xxxxxxxxx>
This patch checks for changes in sink count between short pulse
hpds and forces full detect when there is a change.
This will allow both detection of hotplug and unplug of panels
through dongles that give only short pulse for such events.
v2: changed variable type from u8 to bool (Jani)
return immediately if perform_full_detect is set(Siva)
Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani@xxxxxxxxx>
That's still incomplete since in the hotplug work function we check
whether ->detect status has changed. If that doesn't happen (e.g. sink
count changes from 1->2 or whatever) then we'll fail to generate the
required uevent.
I suspect the only clean way to fix this is to merge all the dp hpd
handling together into one place and stop using ->detect for some parts of
it. Then we would have one place only that decides whether anything
changed, and whether we need to send anything to userspace or not.
-Daniel
i doubt sink count change from 1->2 is valid.
1) we support only edp and SST displays in intel_dp_detect.
we should handle all mst related code in intel_dp_hpd_pulse.
2) check_link_status is called from withing !mst check so i dont see it
change from 1 to 2.
3) even if it changes from 1 to 2, for the given port without mst there
is no way to
switch between first sink to second one outside mst logic.
correct me if i am wrong, the only reason to call intel_dp_detect is to
see if
"one display is connected or disconnected" which i feel is fine with
current code.
But i do agree that we need to clean up intel_dp_hpd_pulse since it does
a lot of things
then repeats those same operations in intel_dp_detect. for example we
read dpcd 0-14,
link status and probe oui only to repeat the same steps in the
intel_dp_detect. considering
that our dpcd read has 1ms delay this can add up pretty quick.
if the intention of intel_dp_hpd_pulse is to handle mst displays, that
should be checked first
and continue only if display is mst otherwise we should just jump to
intel_dp_detect.
---
drivers/gpu/drm/i915/intel_dp.c | 27 ++++++++++++++++++++++-----
1 file changed, 22 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 834f513..279e52c 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4370,26 +4370,39 @@ go_again:
* 4. Check link status on receipt of hot-plug interrupt
*/
static void
-intel_dp_check_link_status(struct intel_dp *intel_dp)
+intel_dp_check_link_status(struct intel_dp *intel_dp, bool *perform_full_detect)
{
struct drm_device *dev = intel_dp_to_dev(intel_dp);
struct intel_encoder *intel_encoder = &dp_to_dig_port(intel_dp)->base;
struct intel_crtc *crtc =
to_intel_crtc(dp_to_dig_port(intel_dp)->base.base.crtc);
u8 sink_irq_vector;
+ u8 old_sink_count = intel_dp->sink_count;
+ bool ret;
u8 link_status[DP_LINK_STATUS_SIZE];
WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
+ *perform_full_detect = false;
+
/* Try to read receiver status if the link appears to be up */
if (!intel_dp_get_link_status(intel_dp, link_status)) {
return;
}
- /* Now read the DPCD to see if it's actually running */
- if (!intel_dp_get_dpcd(intel_dp)) {
+ /* Now read the DPCD to see if it's actually running
+ * Don't return immediately if dpcd read failed,
+ * if sink count was 1 and dpcd read failed we need
+ * to do full detection
+ */
+ ret = intel_dp_get_dpcd(intel_dp);
+
+ if (old_sink_count != intel_dp->sink_count)
+ *perform_full_detect = true;
+
+ /* No need to proceed if we are going to do full detect */
+ if (!ret || *perform_full_detect)
return;
- }
if (!intel_encoder->base.crtc)
return;
@@ -5031,13 +5044,17 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
}
if (!intel_dp->is_mst) {
+ bool full_detect;
/*
* we'll check the link status via the normal hot plug path later -
* but for short hpds we should check it now
*/
drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
- intel_dp_check_link_status(intel_dp);
+ intel_dp_check_link_status(intel_dp, &full_detect);
drm_modeset_unlock(&dev->mode_config.connection_mutex);
+
+ if (full_detect)
+ goto put_power;
}
}
--
1.7.9.5
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--
regards,
Sivakumar
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