[Intel-gfx] [PATCH 14/14] drm/i915: kerneldoc for intel_fifo_underrun.c

[Paulo Zanoni]

2014-09-30 5:56 GMT-03:00 Daniel Vetter <daniel.vetter at ffwll.ch>:
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>

Patch 10/14: Needs rebase, but ok.
Patch 11/14: Ok.
Patch 12/14: Nice one, but:
- I've seen you complaining about lines bigger than 80 columns before,
so I obviously have to do the same here :)
- Can't we now unexport (make them static)
intel_set_{pch,cpu}_fifo_underrun_reporting()? Due to the rebasing
problem I couldn't check this.
Patch 13/14: Ok.
Patch 14/14: Since you recently submitted a patch fixing spelling
errors, I'll ask you to run a spell checker here too. I usually just
go with ":set spell" in the only text editor that exists. Some stuff:
PIPESTATE, occurance, interrup, interrup.

For all patches, with or without changes:
Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>

> ---
>  Documentation/DocBook/drm.tmpl             |  5 ++
>  drivers/gpu/drm/i915/intel_fifo_underrun.c | 82 +++++++++++++++++++++++-------
>  2 files changed, 70 insertions(+), 17 deletions(-)
>
> diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
> index e8ef0f9c7396..9356f16847d9 100644
> --- a/Documentation/DocBook/drm.tmpl
> +++ b/Documentation/DocBook/drm.tmpl
> @@ -3831,6 +3831,11 @@ int num_ioctls;</synopsis>
>  !Fdrivers/gpu/drm/i915/i915_gem.c i915_gem_track_fb
>        </sect2>
>        <sect2>
> +        <title>Display FIFO Underrun Reporting</title>
> +!Pdrivers/gpu/drm/i915/intel_fifo_underrun.c fifo underrun handling
> +!Idrivers/gpu/drm/i915/intel_fifo_underrun.c
> +      </sect2>
> +      <sect2>
>          <title>Plane Configuration</title>
>          <para>
>           This section covers plane configuration and composition with the
> diff --git a/drivers/gpu/drm/i915/intel_fifo_underrun.c b/drivers/gpu/drm/i915/intel_fifo_underrun.c
> index 02909259bfb6..dfffad41664e 100644
> --- a/drivers/gpu/drm/i915/intel_fifo_underrun.c
> +++ b/drivers/gpu/drm/i915/intel_fifo_underrun.c
> @@ -28,6 +28,26 @@
>  #include "i915_drv.h"
>  #include "intel_drv.h"
>
> +/**
> + * DOC: fifo underrun handling
> + *
> + * The i915 driver checks for display fifo underruns using the interrupt signals
> + * provided by the hardware. This is enabled by default and fairly useful to
> + * debug display issues, especially watermark settings.
> + *
> + * If an underrun is detected this is logged into dmesg. To avoid flooding logs
> + * and occupying the cpu underrun interrupts are disabled after the first
> + * occurance until the next modeset on a given pipe.
> + *
> + * Note that underrun detection on gmch platforms is a bit more ugly since there
> + * is no interrupt (despite that the signalling bit is in the PIPESTATE pipe
> + * interrupt register). Also on some other platforms underrun interrupts are
> + * shared, which means that if we detect an underrun we need to disable underrun
> + * reporting on all pipes.
> + *
> + * The code also supports underrun detection on the PCH transcoder.
> + */
> +
>  static bool ivb_can_enable_err_int(struct drm_device *dev)
>  {
>         struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -64,6 +84,14 @@ static bool cpt_can_enable_serr_int(struct drm_device *dev)
>         return true;
>  }
>
> +/**
> + * i9xx_check_fifo_underruns - check for fifo underruns
> + * @dev_priv: i915 device instance
> + *
> + * This function checks for fifo underruns on GMCH platforms. This needs to be
> + * done manually on modeset to make sure that we catch all underruns since they
> + * do not generate an interrupt by themselves on these platforms.
> + */
>  void i9xx_check_fifo_underruns(struct drm_i915_private *dev_priv)
>  {
>         struct intel_crtc *crtc;
> @@ -199,20 +227,6 @@ static void cpt_set_fifo_underrun_reporting(struct drm_device *dev,
>         }
>  }
>
> -/**
> - * intel_set_cpu_fifo_underrun_reporting - enable/disable FIFO underrun messages
> - * @dev: drm device
> - * @pipe: pipe
> - * @enable: true if we want to report FIFO underrun errors, false otherwise
> - *
> - * This function makes us disable or enable CPU fifo underruns for a specific
> - * pipe. Notice that on some Gens (e.g. IVB, HSW), disabling FIFO underrun
> - * reporting for one pipe may also disable all the other CPU error interruts for
> - * the other pipes, due to the fact that there's just one interrupt mask/enable
> - * bit for all the pipes.
> - *
> - * Returns the previous state of underrun reporting.
> - */
>  static bool __intel_set_cpu_fifo_underrun_reporting(struct drm_device *dev,
>                                                     enum pipe pipe, bool enable)
>  {
> @@ -238,6 +252,22 @@ static bool __intel_set_cpu_fifo_underrun_reporting(struct drm_device *dev,
>         return old;
>  }
>
> +/**
> + * intel_set_cpu_fifo_underrun_reporting - set cpu fifo underrrun reporting state
> + * @dev_priv: i915 device instance
> + * @pipe: (CPU) pipe to set state for
> + * @enable: whether underruns should be reported or not
> + *
> + * This function sets the fifo underrun state for @pipe. It is used in the
> + * modeset code to avoid false positives since on many platforms underruns are
> + * expected when disabling or enabling the pipe.
> + *
> + * Notice that on some platforms disabling underrun reports for one pipe
> + * disables for all due to shared interrupts. Actual reporting is still per-pipe
> + * though.
> + *
> + * Returns the previous state of underrun reporting.
> + */
>  bool intel_set_cpu_fifo_underrun_reporting(struct drm_i915_private *dev_priv,
>                                            enum pipe pipe, bool enable)
>  {
> @@ -262,10 +292,10 @@ static bool __cpu_fifo_underrun_reporting_enabled(struct drm_i915_private *dev_p
>  }
>
>  /**
> - * intel_set_pch_fifo_underrun_reporting - enable/disable FIFO underrun messages
> - * @dev: drm device
> + * intel_set_pch_fifo_underrun_reporting - set PCH fifo underrun reporting state
> + * @dev_priv: i915 device instance
>   * @pch_transcoder: the PCH transcoder (same as pipe on IVB and older)
> - * @enable: true if we want to report FIFO underrun errors, false otherwise
> + * @enable: whether underruns should be reported or not
>   *
>   * This function makes us disable or enable PCH fifo underruns for a specific
>   * PCH transcoder. Notice that on some PCHs (e.g. CPT/PPT), disabling FIFO
> @@ -309,6 +339,15 @@ bool intel_set_pch_fifo_underrun_reporting(struct drm_i915_private *dev_priv,
>         return old;
>  }
>
> +/**
> + * intel_pch_fifo_underrun_irq_handler - handle PCH fifo underrun interrup
> + * @dev_priv: i915 device instance
> + * @pipe: (CPU) pipe to set state for
> + *
> + * This handles a CPU fifo underrun interrupt, generating an underrun warning
> + * into dmesg if underrun reporting is enabled and then disables the underrun
> + * interrupt to avoid an irq storm.
> + */
>  void intel_cpu_fifo_underrun_irq_handler(struct drm_i915_private *dev_priv,
>                                          enum pipe pipe)
>  {
> @@ -322,6 +361,15 @@ void intel_cpu_fifo_underrun_irq_handler(struct drm_i915_private *dev_priv,
>                           pipe_name(pipe));
>  }
>
> +/**
> + * intel_pch_fifo_underrun_irq_handler - handle PCH fifo underrun interrup
> + * @dev_priv: i915 device instance
> + * @pch_transcoder: the PCH transcoder (same as pipe on IVB and older)
> + *
> + * This handles a PCH fifo underrun interrupt, generating an underrun warning
> + * into dmesg if underrun reporting is enabled and then disables the underrun
> + * interrupt to avoid an irq storm.
> + */
>  void intel_pch_fifo_underrun_irq_handler(struct drm_i915_private *dev_priv,
>                                          enum transcoder pch_transcoder)
>  {
> --
> 2.1.1
>



-- 
Paulo Zanoni