We might as well dump the drm_file pointer, that's about as useful
a cookie as the pid. Noticed while typing docs for drm_file and friends.

Since the only consumer of this is the tracepoints I think we can safely
change this - those tracepoints should not be uapi relevant at all. It
all goes back to

commit b9c2c9ae
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Thu Jul 1 16:48:09 2010 -0700

    drm: add per-event vblank event trace points

which doesn't give a special justification for using pid over a pointer.

Also note that the nouveau code setting it is entirely pointless:
Since this isn't a vblank event, it will never hit the vblank
tracepoints.

Cc: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: NSean Paul <seanpaul@chromium.org>
Reviewed-by: NLiviu Dudau <Liviu.Dudau@arm.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170308141257.12119-11-daniel.vetter@ffwll.ch

The tracing infrastructure is adding a macro TRACE_SYSTEM_STRING, and
hit the following build failure:

   In file included from include/trace/define_trace.h:90:0,
                    from drivers/gpu/drm/.//radeon/radeon_trace.h:209,
                    from drivers/gpu/drm/.//radeon/radeon_trace_points.c:9:
>> include/trace/ftrace.h:28:0: warning: "TRACE_SYSTEM_STRING" redefined
    #define TRACE_SYSTEM_STRING __app(TRACE_SYSTEM_VAR,__trace_system_name)

Seems that the DRM folks have added their own use to the
TRACE_SYSTEM_STRING, with:

 #define TRACE_SYSTEM_STRING __stringify(TRACE_SYSTEM)

Although, I can not find its use anywhere. I could simply use another
name, but if this macro is not being used, it should be removed.

Link: http://lkml.kernel.org/r/20150402123736.01eda052@gandalf.local.home

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Reviewed-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

seq of a trace point is unsigned int but print format was %d. So
it fixes the format as %u.
Signed-off-by: NSeung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Allows us to track each process that requests and completes events.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Emit a trace point for vblank events.  This can be helpful for mapping
drawing activity against the vblank frequency and period.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDave Airlie <airlied@redhat.com>