Commit 7d14bb6b authored by Daniel Vetter's avatar Daniel Vetter Committed by Dave Airlie

drm: don't call ->firstopen for KMS drivers

It has way too much potential for driver writers to do stupid things
like delayed hw setup because the load sequence is somehow racy (e.g.
the imx driver in staging). So don't call it for modesetting drivers,
which reduces the complexity of the drm core -> driver interface a
notch.

v2: Don't forget to update DocBook.

v3: Go with Laurent's slightly more elaborate proposal for the DocBook
update. Add a few words on top of his diff to elaborate a bit on what
KMS drivers should and shouldn't do in lastclose. There was already a
paragraph present talking about restoring properties, I've simply
extended that one.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 0faa4a87
......@@ -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>
......
......@@ -51,7 +51,8 @@ static int drm_setup(struct drm_device * dev)
int i;
int ret;
if (dev->driver->firstopen) {
if (dev->driver->firstopen &&
!drm_core_check_feature(dev, DRIVER_MODESET)) {
ret = dev->driver->firstopen(dev);
if (ret != 0)
return ret;
......
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