[PATCH] drm: don't call ->firstopen for KMS drivers
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Thu Jul 11 00:54:55 PDT 2013
Hi Daniel,
On Wednesday 10 July 2013 20:17:44 Daniel Vetter wrote:
> 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.
>
> Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
> Documentation/DocBook/drm.tmpl | 2 ++
> drivers/gpu/drm/drm_fops.c | 3 ++-
> 2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
> index 4d54ac8..0e8a5a3 100644
> --- a/Documentation/DocBook/drm.tmpl
> +++ b/Documentation/DocBook/drm.tmpl
> @@ -2423,6 +2423,8 @@ void (*postclose) (struct drm_device *, struct
> drm_file *);</synopsis> <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.
> + Not that this callback is only called for legacy ums drm drivers, not
> + for drm drivers that implement modesetting in the kernel.
> 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
What about
diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
index 7d1278e..afa8d40 100644
--- a/Documentation/DocBook/drm.tmpl
+++ b/Documentation/DocBook/drm.tmpl
@@ -2422,18 +2422,18 @@ 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>
> diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
> index 57e3014..fcde7d4 100644
> --- a/drivers/gpu/drm/drm_fops.c
> +++ b/drivers/gpu/drm/drm_fops.c
> @@ -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;
--
Regards,
Laurent Pinchart
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