From mboxrd@z Thu Jan 1 00:00:00 1970 From: jeff.mcgee@intel.com Subject: [PATCH 1/4] pm_rps: Use unbuffered I/O on sysfs files Date: Fri, 10 Jan 2014 15:12:30 -0600 Message-ID: <1389388353-29980-2-git-send-email-jeff.mcgee@intel.com> References: <1389388353-29980-1-git-send-email-jeff.mcgee@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by gabe.freedesktop.org (Postfix) with ESMTP id 2A934105792 for ; Fri, 10 Jan 2014 13:06:29 -0800 (PST) In-Reply-To: <1389388353-29980-1-git-send-email-jeff.mcgee@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org To: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org From: Jeff McGee Bionic C library may not re-read a buffered, read-only file which results in failure to monitor changes in gt_cur_freq_mhz. Signed-off-by: Jeff McGee --- tests/pm_rps.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/tests/pm_rps.c b/tests/pm_rps.c index e8affdb..9123451 100644 --- a/tests/pm_rps.c +++ b/tests/pm_rps.c @@ -22,6 +22,7 @@ * * Authors: * Ben Widawsky + * Jeff McGee * */ @@ -66,7 +67,6 @@ static int readval(FILE *filp) int val; int scanned; - fflush(filp); rewind(filp); scanned = fscanf(filp, "%d", &val); igt_assert(scanned == 1); @@ -76,15 +76,11 @@ static int readval(FILE *filp) static int do_writeval(FILE *filp, int val, int lerrno) { - /* Must write twice to sysfs since the first one simply calculates the size and won't return the error */ int ret; rewind(filp); ret = fprintf(filp, "%d", val); - rewind(filp); - ret = fprintf(filp, "%d", val); if (ret && lerrno) igt_assert(errno = lerrno); - fflush(filp); return ret; } #define writeval(filp, val) do_writeval(filp, val, 0) @@ -146,6 +142,7 @@ igt_simple_main igt_assert(ret != -1); junk->filp = fopen(path, junk->mode); igt_require(junk->filp); + setbuf(junk->filp, NULL); val = readval(junk->filp); igt_assert(val >= 0); -- 1.8.5.2