From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:49748 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753105AbdJFI4G (ORCPT ); Fri, 6 Oct 2017 04:56:06 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yaroslav Isakov , Len Brown , Sasha Levin Subject: [PATCH 4.9 096/104] tools/power turbostat: bugfix: GFXMHz column not changing Date: Fri, 6 Oct 2017 10:52:14 +0200 Message-Id: <20171006083855.024728821@linuxfoundation.org> In-Reply-To: <20171006083840.743659740@linuxfoundation.org> References: <20171006083840.743659740@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Len Brown [ Upstream commit 22048c5485503749754b3b5daf9d99ef89fcacdc ] turbostat displays a GFXMHz column, which comes from reading /sys/class/graphics/fb0/device/drm/card0/gt_cur_freq_mhz But GFXMHz was not changing, even when a manual cat /sys/class/graphics/fb0/device/drm/card0/gt_cur_freq_mhz showed a new value. It turns out that a rewind() on the open file is not sufficient, fflush() (or a close/open) is needed to read fresh values. Reported-by: Yaroslav Isakov Signed-off-by: Len Brown Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- tools/power/x86/turbostat/turbostat.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/tools/power/x86/turbostat/turbostat.c +++ b/tools/power/x86/turbostat/turbostat.c @@ -2003,8 +2003,10 @@ int snapshot_gfx_mhz(void) if (fp == NULL) fp = fopen_or_die("/sys/class/graphics/fb0/device/drm/card0/gt_cur_freq_mhz", "r"); - else + else { rewind(fp); + fflush(fp); + } retval = fscanf(fp, "%d", &gfx_cur_mhz); if (retval != 1)