@@ -311,16 +311,6 @@ void drm_dp_cec_attach(struct drm_dp_aux *aux, u16 source_physical_address)
if (!aux->transfer)
return;
-#ifndef CONFIG_MEDIA_CEC_RC
- /*
- * CEC_CAP_RC is part of CEC_CAP_DEFAULTS, but it is stripped by
- * cec_allocate_adapter() if CONFIG_MEDIA_CEC_RC is undefined.
- *
- * Do this here as well to ensure the tests against cec_caps are
- * correct.
- */
- cec_caps &= ~CEC_CAP_RC;
-#endif
cancel_delayed_work_sync(&aux->cec.unregister_work);
mutex_lock(&aux->cec.lock);
@@ -337,7 +327,9 @@ void drm_dp_cec_attach(struct drm_dp_aux *aux, u16 source_physical_address)
num_las = CEC_MAX_LOG_ADDRS;
if (aux->cec.adap) {
- if (aux->cec.adap->capabilities == cec_caps &&
+ /* Check if the adapter properties have changed */
+ if ((aux->cec.adap->capabilities & CEC_CAP_MONITOR_ALL) ==
+ (cec_caps & CEC_CAP_MONITOR_ALL) &&
aux->cec.adap->available_log_addrs == num_las) {
/* Unchanged, so just set the phys addr */
cec_s_phys_addr(aux->cec.adap, source_physical_address, false);
If the hotplug detect of a display is low for longer than one second (configurable through drm_dp_cec_unregister_delay), then the CEC adapter is unregistered since we assume the display was disconnected. If the HPD went low for less than one second, then we check if the properties of the CEC adapter have changed, since that indicates that we actually switch to new hardware and we have to unregister the old CEC device and register a new one. Unfortunately, the test for changed properties was written poorly, and after a new CEC capability was added to the CEC core code the test always returned true (i.e. the properties had changed). As a result the CEC device was unregistered and re-registered for every HPD toggle. If the CEC remote controller integration was also enabled (CONFIG_MEDIA_CEC_RC was set), then the corresponding input device was also unregistered and re-registered. As a result the input device in /sys would keep incrementing its number, e.g.: /sys/devices/pci0000:00/0000:00:08.1/0000:e7:00.0/rc/rc0/input20 Since short HPD toggles are common, the number could over time get into the thousands. While not a serious issue (i.e. nothing crashes), it is not intended to work that way. This patch changes the test so that it only checks for the single CEC capability that can actually change, and it ignores any other capabilities, so this is now safe as well if new caps are added in the future. With the changed test the bit under #ifndef CONFIG_MEDIA_CEC_RC can be dropped as well, so that's a nice cleanup. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Reported-by: Farblos <farblos@vodafonemail.de> --- Jens (aka Farblos), can you test this patch? --- drivers/gpu/drm/display/drm_dp_cec.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-)