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-rw-r--r--Documentation/DocBook/drm.tmpl27
1 files changed, 16 insertions, 11 deletions
diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
index 6869b9b534b5..9fc8ed4ac0f4 100644
--- a/Documentation/DocBook/drm.tmpl
+++ b/Documentation/DocBook/drm.tmpl
@@ -2405,18 +2405,18 @@ void (*postclose) (struct drm_device *, struct drm_file *);</synopsis>
</abstract>
<para>
The <methodname>firstopen</methodname> method is called by the DRM core
- when an application opens a device that has no other opened file handle.
- Similarly the <methodname>lastclose</methodname> method is called when
- the last application holding a file handle opened on the device closes
- it. Both methods are mostly used for UMS (User Mode Setting) drivers to
- acquire and release device resources which should be done in the
- <methodname>load</methodname> and <methodname>unload</methodname>
- methods for KMS drivers.
+ for legacy UMS (User Mode Setting) drivers only when an application
+ opens a device that has no other opened file handle. UMS drivers can
+ implement it to acquire device resources. KMS drivers can't use the
+ method and must acquire resources in the <methodname>load</methodname>
+ method instead.
</para>
<para>
- Note that the <methodname>lastclose</methodname> method is also called
- at module unload time or, for hot-pluggable devices, when the device is
- unplugged. The <methodname>firstopen</methodname> and
+ Similarly the <methodname>lastclose</methodname> method is called when
+ the last application holding a file handle opened on the device closes
+ it, for both UMS and KMS drivers. Additionally, the method is also
+ called at module unload time or, for hot-pluggable devices, when the
+ device is unplugged. The <methodname>firstopen</methodname> and
<methodname>lastclose</methodname> calls can thus be unbalanced.
</para>
<para>
@@ -2445,7 +2445,12 @@ void (*postclose) (struct drm_device *, struct drm_file *);</synopsis>
<para>
The <methodname>lastclose</methodname> method should restore CRTC and
plane properties to default value, so that a subsequent open of the
- device will not inherit state from the previous user.
+ device will not inherit state from the previous user. It can also be
+ used to execute delayed power switching state changes, e.g. in
+ conjunction with the vga-switcheroo infrastructure. Beyond that KMS
+ drivers should not do any further cleanup. Only legacy UMS drivers might
+ need to clean up device state so that the vga console or an independent
+ fbdev driver could take over.
</para>
</sect2>
<sect2>