From: Len Brown <len.brown@intel.com>
Date: Sat, 4 Mar 2017 20:42:48 +0000 (-0500)
Subject: tools/power turbostat: bugfix: GFXMHz column not changing
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=22048c5485503749754b3b5daf9d99ef89fcacdc;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

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>
---

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 828dccd3f01e..d7fb6bcb2744 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -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)