Commit 22048c54 authored Mar 04, 2017 by Len Brown

tools/power turbostat: bugfix: GFXMHz column not changing



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>

parent e3942ed8

tools/power/x86/turbostat/turbostat.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -2485,8 +2485,10 @@ 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)

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