Commit 86c469be authored Mar 04, 2017 by Len Brown Committed by Greg Kroah-Hartman Oct 08, 2017

tools/power turbostat: bugfix: GFXMHz column not changing




[ 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 <yaroslav.isakov@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent c126bc6b

tools/power/x86/turbostat/turbostat.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -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)