diff options
Diffstat (limited to 'Documentation/DocBook')
| -rw-r--r-- | Documentation/DocBook/drm.tmpl | 27 |
1 files changed, 16 insertions, 11 deletions
diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl index 6869b9b534b..9fc8ed4ac0f 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> |