On Wed, 26 Sep 2018, Guang Bai <guang.bai@xxxxxxxxx> wrote: > On Wed, 26 Sep 2018 16:44:16 -0700 > Guang Bai <guang.bai@xxxxxxxxx> wrote: > >> On Tue, 25 Sep 2018 10:18:36 +0300 >> Jani Nikula <jani.nikula@xxxxxxxxx> wrote: >> >> > On some systems we get the hotplug irq on unplug before the DDC pins >> > have been disconnected, resulting in connector status remaining >> > connected. Since previous attempts at using hotplug live status >> > before DDC have failed, the only viable option is to reduce the >> > window for mistakes. Delay the hotplug processing. >> > >> > Reference: >> > http://mid.mail-archive.com/CAB4CAwcfj32FovZwpTbekvHpoc3gG0sVbNtW8jeXRcp5qwEsmw@xxxxxxxxxxxxxx >> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107125 >> > Reported-by: Chris Chiu <chiu@xxxxxxxxxxxx> Tested-by: Chris Chiu >> > <chiu@xxxxxxxxxxxx> Cc: Chris Chiu <chiu@xxxxxxxxxxxx> >> > Cc: Guang Bai <guang.bai@xxxxxxxxx> >> > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> >> > Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> >> > --- >> > drivers/gpu/drm/i915/i915_drv.h | 2 +- >> > drivers/gpu/drm/i915/intel_hotplug.c | 16 +++++++++++----- >> > 2 files changed, 12 insertions(+), 6 deletions(-) >> > >> > diff --git a/drivers/gpu/drm/i915/i915_drv.h >> > b/drivers/gpu/drm/i915/i915_drv.h index 8624b4bdc242..4378be7a20d5 >> > 100644 --- a/drivers/gpu/drm/i915/i915_drv.h >> > +++ b/drivers/gpu/drm/i915/i915_drv.h >> > @@ -286,7 +286,7 @@ enum hpd_pin { >> > #define HPD_STORM_DEFAULT_THRESHOLD 5 >> > >> > struct i915_hotplug { >> > - struct work_struct hotplug_work; >> > + struct delayed_work hotplug_work; >> > >> > struct { >> > unsigned long last_jiffies; >> > diff --git a/drivers/gpu/drm/i915/intel_hotplug.c >> > b/drivers/gpu/drm/i915/intel_hotplug.c index >> > 648a13c6043c..ce9bedbedcd1 100644 --- >> > a/drivers/gpu/drm/i915/intel_hotplug.c +++ >> > b/drivers/gpu/drm/i915/intel_hotplug.c @@ -110,6 +110,9 @@ enum >> > hpd_pin intel_hpd_pin_default(struct drm_i915_private *dev_priv, } >> > } >> > >> > +/* Delay between irq and hotplug detect processing */ >> > +#define HOTPLUG_DELAY_MS 300 >> > + >> > #define HPD_STORM_DETECT_PERIOD 1000 >> > #define HPD_STORM_REENABLE_DELAY (2 * 60 * 1000) >> > >> > @@ -319,7 +322,8 @@ static void i915_digport_work_func(struct >> > work_struct *work) spin_lock_irq(&dev_priv->irq_lock); >> > dev_priv->hotplug.event_bits |= old_bits; >> > spin_unlock_irq(&dev_priv->irq_lock); >> > - schedule_work(&dev_priv->hotplug.hotplug_work); >> > + >> > schedule_delayed_work(&dev_priv->hotplug.hotplug_work, >> > + >> > msecs_to_jiffies(HOTPLUG_DELAY_MS)); } >> > } >> > >> > @@ -329,7 +333,7 @@ static void i915_digport_work_func(struct >> > work_struct *work) static void i915_hotplug_work_func(struct >> > work_struct *work) { >> > struct drm_i915_private *dev_priv = >> > - container_of(work, struct drm_i915_private, >> > hotplug.hotplug_work); >> > + container_of(work, struct drm_i915_private, >> > hotplug.hotplug_work.work); struct drm_device *dev = &dev_priv->drm; >> > struct intel_connector *intel_connector; >> > struct intel_encoder *intel_encoder; >> > @@ -466,7 +470,8 @@ void intel_hpd_irq_handler(struct >> > drm_i915_private *dev_priv, if (queue_dig) >> > queue_work(dev_priv->hotplug.dp_wq, >> > &dev_priv->hotplug.dig_port_work); if (queue_hp) >> > - schedule_work(&dev_priv->hotplug.hotplug_work); >> > + >> > schedule_delayed_work(&dev_priv->hotplug.hotplug_work, >> > + >> > msecs_to_jiffies(HOTPLUG_DELAY_MS)); } >> > >> > /** >> > @@ -586,7 +591,8 @@ void intel_hpd_poll_init(struct drm_i915_private >> > *dev_priv) >> > void intel_hpd_init_work(struct drm_i915_private *dev_priv) >> > { >> > - INIT_WORK(&dev_priv->hotplug.hotplug_work, >> > i915_hotplug_work_func); >> > + INIT_DELAYED_WORK(&dev_priv->hotplug.hotplug_work, >> > + i915_hotplug_work_func); >> > INIT_WORK(&dev_priv->hotplug.dig_port_work, >> > i915_digport_work_func); >> > INIT_WORK(&dev_priv->hotplug.poll_init_work, >> > i915_hpd_poll_init_work); >> > INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work, @@ -604,7 >> > +610,7 @@ void intel_hpd_cancel_work(struct drm_i915_private >> > *dev_priv) spin_unlock_irq(&dev_priv->irq_lock); >> > cancel_work_sync(&dev_priv->hotplug.dig_port_work); >> > - cancel_work_sync(&dev_priv->hotplug.hotplug_work); >> > + cancel_delayed_work_sync(&dev_priv->hotplug.hotplug_work); >> > cancel_work_sync(&dev_priv->hotplug.poll_init_work); >> > cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work); >> > } >> Jani - With these changes, my customer platform still fails the >> HDMI hot-plug test - slowly unplug the HDMI cable, >> the /sys/class/drm/card0/card0-HDMI-A-1/status still shows connected >> state. My previous experiments indicated adding bigger delay before >> calling "drm_kms_helper_hotplug_event(dev)", which lead to reading the >> EDID, didn't have solid passing test results. The POC changes with >> passing results from onsite utilize following algorithm - >> 1. in the hot-plug worker function, check the PCH hot-plug status pin >> to see it's disconnected or not in a 3 x 100ms loop >> 2. if "disconnected" is confirmed after this loop, honor it and do not >> read the EDID >> 3. if "connected" is confirmed after this loop, honor it after EDID >> read is successful >> The overhead for this algorithm is to access the HPD status from all >> platform PCHs and some hot-plug code refactoring would be needed. >> (sorry for the late reply as of customer platform preparations, etc) >> > Double checked my archives - the EDID reading is actually done in the > "intel_encoder->hotplug()" via "drm_helper_probe_detect()" > sorry for the typo. Earlier attempts at utilizing the hotplug live status in the work function have failed; it's not universally reliable. With that, you basically need to have a time threshold between hotplug irq and DDC disconnect. Slower than that, it will fail. How slow is acceptable? BR, Jani. -- Jani Nikula, Intel Open Source Graphics Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
