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

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

Documentation/DocBook/drm.tmpl

+16 −11
Original line number Diff line number Diff line
@@ -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>

drivers/gpu/drm/drm_fops.c

+2 −1
Original line number Diff line number Diff line
@@ -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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