4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Len Brown <[email protected]> [ 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 <[email protected]> Signed-off-by: Len Brown <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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)
