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-rw-r--r--Documentation/DocBook/drm.tmpl78
1 files changed, 64 insertions, 14 deletions
diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
index 4ee2304f82f..f9df3b872c1 100644
--- a/Documentation/DocBook/drm.tmpl
+++ b/Documentation/DocBook/drm.tmpl
@@ -743,6 +743,10 @@ char *date;</synopsis>
These two operations are mandatory for GEM drivers that support DRM
PRIME.
</para>
+ <sect4>
+ <title>DRM PRIME Helper Functions Reference</title>
+!Pdrivers/gpu/drm/drm_prime.c PRIME Helpers
+ </sect4>
</sect3>
<sect3 id="drm-gem-objects-mapping">
<title>GEM Objects Mapping</title>
@@ -978,10 +982,25 @@ int max_width, max_height;</synopsis>
If the parameters are deemed valid, drivers then create, initialize and
return an instance of struct <structname>drm_framebuffer</structname>.
If desired the instance can be embedded in a larger driver-specific
- structure. The new instance is initialized with a call to
- <function>drm_framebuffer_init</function> which takes a pointer to DRM
- frame buffer operations (struct
- <structname>drm_framebuffer_funcs</structname>). Frame buffer operations are
+ structure. Drivers must fill its <structfield>width</structfield>,
+ <structfield>height</structfield>, <structfield>pitches</structfield>,
+ <structfield>offsets</structfield>, <structfield>depth</structfield>,
+ <structfield>bits_per_pixel</structfield> and
+ <structfield>pixel_format</structfield> fields from the values passed
+ through the <parameter>drm_mode_fb_cmd2</parameter> argument. They
+ should call the <function>drm_helper_mode_fill_fb_struct</function>
+ helper function to do so.
+ </para>
+
+ <para>
+ The initailization of the new framebuffer instance is finalized with a
+ call to <function>drm_framebuffer_init</function> which takes a pointer
+ to DRM frame buffer operations (struct
+ <structname>drm_framebuffer_funcs</structname>). Note that this function
+ publishes the framebuffer and so from this point on it can be accessed
+ concurrently from other threads. Hence it must be the last step in the
+ driver's framebuffer initialization sequence. Frame buffer operations
+ are
<itemizedlist>
<listitem>
<synopsis>int (*create_handle)(struct drm_framebuffer *fb,
@@ -1022,16 +1041,16 @@ int max_width, max_height;</synopsis>
</itemizedlist>
</para>
<para>
- After initializing the <structname>drm_framebuffer</structname>
- instance drivers must fill its <structfield>width</structfield>,
- <structfield>height</structfield>, <structfield>pitches</structfield>,
- <structfield>offsets</structfield>, <structfield>depth</structfield>,
- <structfield>bits_per_pixel</structfield> and
- <structfield>pixel_format</structfield> fields from the values passed
- through the <parameter>drm_mode_fb_cmd2</parameter> argument. They
- should call the <function>drm_helper_mode_fill_fb_struct</function>
- helper function to do so.
- </para>
+ The lifetime of a drm framebuffer is controlled with a reference count,
+ drivers can grab additional references with
+ <function>drm_framebuffer_reference</function> </para> and drop them
+ again with <function>drm_framebuffer_unreference</function>. For
+ driver-private framebuffers for which the last reference is never
+ dropped (e.g. for the fbdev framebuffer when the struct
+ <structname>drm_framebuffer</structname> is embedded into the fbdev
+ helper struct) drivers can manually clean up a framebuffer at module
+ unload time with
+ <function>drm_framebuffer_unregister_private</function>.
</sect2>
<sect2>
<title>Output Polling</title>
@@ -1043,6 +1062,22 @@ int max_width, max_height;</synopsis>
operation.
</para>
</sect2>
+ <sect2>
+ <title>Locking</title>
+ <para>
+ Beside some lookup structures with their own locking (which is hidden
+ behind the interface functions) most of the modeset state is protected
+ by the <code>dev-&lt;mode_config.lock</code> mutex and additionally
+ per-crtc locks to allow cursor updates, pageflips and similar operations
+ to occur concurrently with background tasks like output detection.
+ Operations which cross domains like a full modeset always grab all
+ locks. Drivers there need to protect resources shared between crtcs with
+ additional locking. They also need to be careful to always grab the
+ relevant crtc locks if a modset functions touches crtc state, e.g. for
+ load detection (which does only grab the <code>mode_config.lock</code>
+ to allow concurrent screen updates on live crtcs).
+ </para>
+ </sect2>
</sect1>
<!-- Internals: kms initialization and cleanup -->
@@ -1126,6 +1161,12 @@ int max_width, max_height;</synopsis>
any new rendering to the frame buffer until the page flip completes.
</para>
<para>
+ If a page flip can be successfully scheduled the driver must set the
+ <code>drm_crtc-&lt;fb</code> field to the new framebuffer pointed to
+ by <code>fb</code>. This is important so that the reference counting
+ on framebuffers stays balanced.
+ </para>
+ <para>
If a page flip is already pending, the
<methodname>page_flip</methodname> operation must return
-<errorname>EBUSY</errorname>.
@@ -1609,6 +1650,10 @@ void intel_crt_init(struct drm_device *dev)
make its properties available to applications.
</para>
</sect2>
+ <sect2>
+ <title>KMS API Functions</title>
+!Edrivers/gpu/drm/drm_crtc.c
+ </sect2>
</sect1>
<!-- Internals: kms helper functions -->
@@ -2104,6 +2149,7 @@ void intel_crt_init(struct drm_device *dev)
<title>fbdev Helper Functions Reference</title>
!Pdrivers/gpu/drm/drm_fb_helper.c fbdev helpers
!Edrivers/gpu/drm/drm_fb_helper.c
+!Iinclude/drm/drm_fb_helper.h
</sect2>
<sect2>
<title>Display Port Helper Functions Reference</title>
@@ -2111,6 +2157,10 @@ void intel_crt_init(struct drm_device *dev)
!Iinclude/drm/drm_dp_helper.h
!Edrivers/gpu/drm/drm_dp_helper.c
</sect2>
+ <sect2>
+ <title>EDID Helper Functions Reference</title>
+!Edrivers/gpu/drm/drm_edid.c
+ </sect2>
</sect1>
<!-- Internals: vertical blanking -->