[PATCH 1/2] drm/i915/audio: clarify HD audio documentation wrt modeset

[PATCH 1/2] drm/i915/audio: clarify HD audio documentation wrt modeset

[Jani Nikula]

Clarify that audio enable/disable sequences are part of the modeset
sequence.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/intel_audio.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
index 3da9b8409f20..dc32cf4585f8 100644
--- a/drivers/gpu/drm/i915/intel_audio.c
+++ b/drivers/gpu/drm/i915/intel_audio.c
@@ -41,7 +41,8 @@
  *
  * The disable sequences must be performed before disabling the transcoder or
  * port. The enable sequences may only be performed after enabling the
- * transcoder and port, and after completed link training.
+ * transcoder and port, and after completed link training. Therefore the audio
+ * enable/disable sequences are part of the modeset sequence.
  *
  * The codec and controller sequences could be done either parallel or serial,
  * but generally the ELDV/PD change in the codec sequence indicates to the audio
-- 
2.1.4

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[PATCH 2/2] drm/i915/hotplug: document the hotplug handling in the driver

[Jani Nikula]

Add an overview of the drm/i915 hotplug handling.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 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) {
-- 
2.1.4

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Re: [PATCH 2/2] drm/i915/hotplug: document the hotplug handling in the driver

[shuang.he]

Tested-By: Intel Graphics QA PRTS (Patch Regression Test System Contact: shuang.he@intel.com)
Task id: 6708
-------------------------------------Summary-------------------------------------
Platform          Delta          drm-intel-nightly          Series Applied
ILK                                  302/302              302/302
SNB                                  312/316              312/316
IVB                                  343/343              343/343
BYT                 -3              287/287              284/287
HSW                                  380/380              380/380
-------------------------------------Detailed-------------------------------------
Platform  Test                                drm-intel-nightly          Series Applied
*BYT  igt@gem_partial_pwrite_pread@reads      PASS(1)      FAIL(1)
*BYT  igt@gem_partial_pwrite_pread@reads-display      PASS(1)      FAIL(1)
*BYT  igt@gem_partial_pwrite_pread@reads-uncached      PASS(1)      FAIL(1)
Note: You need to pay more attention to line start with '*'
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Re: [PATCH 2/2] drm/i915/hotplug: document the hotplug handling in the driver

[Sivakumar Thulasimani]

On 7/2/2015 6:35 PM, Jani Nikula wrote:
> Add an overview of the drm/i915 hotplug handling.
>
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> ---
>   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) {
can we add that HPD storm is not expected in case of Displayport as 
discussed in other thread and
so is not handled in i915_digport_work_func ?

-- 
regards,
Sivakumar

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Re: [PATCH 2/2] drm/i915/hotplug: document the hotplug handling in the driver

[Daniel Vetter]

On Mon, Jul 06, 2015 at 12:26:15PM +0530, Sivakumar Thulasimani wrote:
> 
> 
> On 7/2/2015 6:35 PM, Jani Nikula wrote:
> >Add an overview of the drm/i915 hotplug handling.
> >
> >Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> >---
> >  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) {
> can we add that HPD storm is not expected in case of Displayport as
> discussed in other thread and
> so is not handled in i915_digport_work_func ?

Good suggestion, but Jani's on vacation now for a few weeks. Can you pls
submit a follow-up patch to add that? I've merged these two meanwhile.

Thanks, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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