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[PATCH for 4.9 39/39] tools/power turbostat: bugfix: GFXMHz column not changing

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From: Len Brown <len.brown@intel.com>

[ 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>
---
 tools/power/x86/turbostat/turbostat.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 3e199b508a96..9664b1ff4285 100644
--- 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)
-- 
2.11.0

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[PATCH for 4.9 18/39] iommu/exynos: Block SYSMMU while invalidating  FLPD cache "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 27/39] x86/acpi: Restore the order of CPU IDs "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 22/39] netfilter: nfnl_cthelper: fix incorrect  helper->expect_class_max "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 35/39] xfs: remove kmem_zalloc_greedy "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 31/39] rds: ib: add error handle "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 24/39] nfs: make nfs4_cb_sv_ops static "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 32/39] md/raid10: submit bio directly to replacement  disk "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 38/39] ARM: dts: BCM5301X: Fix memory start address "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 29/39] arm64: kasan: avoid bad virt_to_pfn() "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 39/39] tools/power turbostat: bugfix: GFXMHz column  not changing "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 20/39] MIPS: smp-cps: Fix retrieval of VPE mask on big  endian CPUs "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 28/39] iommu/io-pgtable-arm: Check for leaf entry  before dereferencing it "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 23/39] parisc: perf: Fix potential NULL pointer  dereference "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 34/39] i2c: meson: fix wrong variable usage in  meson_i2c_put_data "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 36/39] ASoC: wm_adsp: Return an error on write to a  disabled volatile control "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 25/39] ibmvnic: Free tx/rx scrq pointer array when  releasing sub-crqs "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 33/39] netfilter: nf_tables: set pktinfo->thoff at AH  header if found "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 37/39] libata: transport: Remove circular dependency  at free time "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200

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