From: Prarit Bhargava Date: Thu, 15 Dec 2022 15:18:16 +0000 (-0500) Subject: tools/power turbostat: Fix /dev/cpu_dma_latency warnings X-Git-Tag: v6.2.10~130 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1b0878fe489168f1047a55178c65f01bf7647194;p=thirdparty%2Fkernel%2Fstable.git tools/power turbostat: Fix /dev/cpu_dma_latency warnings [ Upstream commit 40aafc7d58d3544f152a863a0e9863014b6d5d8c ] When running as non-root the following error is seen in turbostat: turbostat: fopen /dev/cpu_dma_latency : Permission denied turbostat and the man page have information on how to avoid other permission errors, so these can be fixed the same way. Provide better /dev/cpu_dma_latency warnings that provide instructions on how to avoid the error, and update the man page. Signed-off-by: Prarit Bhargava Cc: linux-pm@vger.kernel.org Signed-off-by: Len Brown Signed-off-by: Sasha Levin --- diff --git a/tools/power/x86/turbostat/turbostat.8 b/tools/power/x86/turbostat/turbostat.8 index c7b26a3603afe..3e1a4c4be001a 100644 --- a/tools/power/x86/turbostat/turbostat.8 +++ b/tools/power/x86/turbostat/turbostat.8 @@ -344,6 +344,8 @@ Alternatively, non-root users can be enabled to run turbostat this way: # chmod +r /dev/cpu/*/msr +# chmod +r /dev/cpu_dma_latency + .B "turbostat " reads hardware counters, but doesn't write them. So it will not interfere with the OS or other programs, including diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c index aba460410dbd1..c24054e3ef7ad 100644 --- a/tools/power/x86/turbostat/turbostat.c +++ b/tools/power/x86/turbostat/turbostat.c @@ -5482,7 +5482,7 @@ void print_dev_latency(void) retval = read(fd, (void *)&value, sizeof(int)); if (retval != sizeof(int)) { - warn("read %s\n", path); + warn("read failed %s\n", path); close(fd); return; }