On 7/2/2015 6:35 PM, Jani Nikula wrote:
can we add that HPD storm is not expected in case of Displayport as discussed in other thread andAdd an overview of the drm/i915 hotplug handling. Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> --- Documentation/DocBook/drm.tmpl | 5 +++++ drivers/gpu/drm/i915/intel_hotplug.c | 39 ++++++++++++++++++++++++++++++++++++ 2 files changed, 44 insertions(+) diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl index c0312cbd023d..e82205ee3d5f 100644 --- a/Documentation/DocBook/drm.tmpl +++ b/Documentation/DocBook/drm.tmpl @@ -4045,6 +4045,11 @@ int num_ioctls;</synopsis> </para> </sect2> <sect2> + <title>Hotplug</title> +!Pdrivers/gpu/drm/i915/intel_hotplug.c Hotplug +!Idrivers/gpu/drm/i915/intel_hotplug.c + </sect2> + <sect2> <title>High Definition Audio</title> !Pdrivers/gpu/drm/i915/intel_audio.c High Definition Audio over HDMI and Display Port !Idrivers/gpu/drm/i915/intel_audio.c diff --git a/drivers/gpu/drm/i915/intel_hotplug.c b/drivers/gpu/drm/i915/intel_hotplug.c index 3c53aac71d98..bac91a158ca2 100644 --- a/drivers/gpu/drm/i915/intel_hotplug.c +++ b/drivers/gpu/drm/i915/intel_hotplug.c @@ -29,6 +29,45 @@ #include "i915_drv.h" #include "intel_drv.h"+/**+ * DOC: Hotplug + * + * Simply put, hotplug occurs when a display is connected to or disconnected + * from the system. However, there may be adapters and docking stations and + * Display Port short pulses and MST devices involved, complicating matters. + * + * Hotplug in i915 is handled in many different levels of abstraction. + * + * The platform dependent interrupt handling code in i915_irq.c enables, + * disables, and does preliminary handling of the interrupts. The interrupt + * handlers gather the hotplug detect (HPD) information from relevant registers + * into a platform independent mask of hotplug pins that have fired. + * + * The platform independent interrupt handler intel_hpd_irq_handler() in + * intel_hotplug.c does hotplug irq storm detection and mitigation, and passes + * further processing to appropriate bottom halves (Display Port specific and + * regular hotplug). + * + * The Display Port work function i915_digport_work_func() calls into + * intel_dp_hpd_pulse() via hooks, which handles DP short pulses and DP MST long + * pulses, with failures and non-MST long pulses triggering regular hotplug + * processing on the connector. + * + * The regular hotplug work function i915_hotplug_work_func() calls connector + * detect hooks, and, if connector status changes, triggers sending of hotplug + * uevent to userspace via drm_kms_helper_hotplug_event(). + * + * Finally, the userspace is responsible for triggering a modeset upon receiving + * the hotplug uevent, disabling or enabling the crtc as needed. + * + * The hotplug interrupt storm detection and mitigation code keeps track of the + * number of interrupts per hotplug pin per a period of time, and if the number + * of interrupts exceeds a certain threshold, the interrupt is disabled for a + * while before being re-enabled. The intention is to mitigate issues raising + * from broken hardware triggering massive amounts of interrupts and grinding + * the system to a halt. + */ + enum port intel_hpd_pin_to_port(enum hpd_pin pin) { switch (pin) {
so is not handled in i915_digport_work_func ? -- regards, Sivakumar _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
