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authorDaniel Vetter <daniel.vetter@ffwll.ch>2013-08-08 15:41:23 +0200
committerDave Airlie <airlied@redhat.com>2013-08-19 02:05:17 +0200
commitb0e898ac555e96e7863a5ee95d70f3625f1db5e2 (patch)
tree6b2b00af9c5368b068b0c77d58fff1f1990f311b /drivers/staging
parentdrm/vmwgfx: remove redundant clearing of driver->dma_quiescent (diff)
downloadlinux-b0e898ac555e96e7863a5ee95d70f3625f1db5e2.tar.xz
linux-b0e898ac555e96e7863a5ee95d70f3625f1db5e2.zip
drm: remove FASYNC support
So I've stumbled over drm_fasync and wondered what it does. Digging that up is quite a story. First I've had to read up on what this does and ended up being rather bewildered why peopled loved signals so much back in the days that they've created SIGIO just for that ... Then I wondered how this ever works, and what that strange "No-op." comment right above it should mean. After all calling the core fasync helper is pretty obviously not a noop. After reading through the kernels FASYNC implementation I've noticed that signals are only sent out to the processes attached with FASYNC by calling kill_fasync. No merged drm driver has ever done that. After more digging I've found out that the only driver that ever used this is the so called GAMMA driver. I've frankly never heard of such a gpu brand ever before. Now FASYNC seems to not have been the only bad thing with that driver, since Dave Airlie removed it from the drm driver with prejudice: commit 1430163b4bbf7b00367ea1066c1c5fe85dbeefed Author: Dave Airlie <airlied@linux.ie> Date: Sun Aug 29 12:04:35 2004 +0000 Drop GAMMA DRM from a great height ... Long story short, the drm fasync support seems to be doing absolutely nothing. And the only user of it was never merged into the upstream kernel. And we don't need any fops->fasync callback since the fcntl implementation in the kernel already implements the noop case correctly. So stop this particular cargo-cult and rip it all out. v2: Kill drm_fasync assignments in rcar (newly added) and imx drivers (somehow I've missed that one in staging). Also drop the reference in the drm DocBook. ARM compile-fail reported by Rob Clark. v3: Move the removal of dev->buf_asnyc assignment in drm_setup to this patch here. v4: Actually git add ... tsk. Cc: Dave Airlie <airlied@linux.ie> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Rob Clark <robdclark@gmail.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers/staging')
-rw-r--r--drivers/staging/imx-drm/imx-drm-core.c1
1 files changed, 0 insertions, 1 deletions
diff --git a/drivers/staging/imx-drm/imx-drm-core.c b/drivers/staging/imx-drm/imx-drm-core.c
index a8900496b980..29607c25b261 100644
--- a/drivers/staging/imx-drm/imx-drm-core.c
+++ b/drivers/staging/imx-drm/imx-drm-core.c
@@ -207,7 +207,6 @@ static const struct file_operations imx_drm_driver_fops = {
.unlocked_ioctl = drm_ioctl,
.mmap = drm_gem_cma_mmap,
.poll = drm_poll,
- .fasync = drm_fasync,
.read = drm_read,
.llseek = noop_llseek,
};