i965: don't require 64bit cmpxchg

There are still some distributions trying to support unfortunate people
with old or exotic CPUs that don't have 64bit atomic operations. The
only thing preventing compile of the Intel driver for them seems to be
initialization of a debug variable.

v2: use call_once() instead of unsafe code, as suggested by Matt Turner

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93089
Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
This commit is contained in:
Grazvydas Ignotas 2017-03-05 23:23:25 +02:00 committed by Matt Turner
parent 290d7e892d
commit b384c23b9e

View file

@ -33,8 +33,8 @@
#include "common/gen_debug.h"
#include "util/macros.h"
#include "util/u_atomic.h" /* for p_atomic_cmpxchg */
#include "util/debug.h"
#include "c11/threads.h"
uint64_t INTEL_DEBUG = 0;
@ -101,9 +101,17 @@ intel_debug_flag_for_shader_stage(gl_shader_stage stage)
return flags[stage];
}
static void
brw_process_intel_debug_variable_once(void)
{
INTEL_DEBUG = parse_debug_string(getenv("INTEL_DEBUG"), debug_control);
}
void
brw_process_intel_debug_variable(void)
{
uint64_t intel_debug = parse_debug_string(getenv("INTEL_DEBUG"), debug_control);
(void) p_atomic_cmpxchg(&INTEL_DEBUG, 0, intel_debug);
static once_flag process_intel_debug_variable_flag = ONCE_FLAG_INIT;
call_once(&process_intel_debug_variable_flag,
brw_process_intel_debug_variable_once);
}