From: Prarit Bhargava <prarit@xxxxxxxxxx>
[ 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 <prarit@xxxxxxxxxx>
Cc: linux-pm@xxxxxxxxxxxxxxx
Signed-off-by: Len Brown <len.brown@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
tools/power/x86/turbostat/turbostat.8 | 2 ++
tools/power/x86/turbostat/turbostat.c | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)
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;
}
--
2.39.2
