This is a note to let you know that I've just added the patch titled
tools/power turbostat: Fix /dev/cpu_dma_latency warnings
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tools-power-turbostat-fix-dev-cpu_dma_latency-warnin.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 05f1bfec1e72aa26791a8fd0ca0e517e4d3375e4
Author: Prarit Bhargava <prarit@xxxxxxxxxx>
Date: Thu Dec 15 10:18:16 2022 -0500
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 <prarit@xxxxxxxxxx>
Cc: linux-pm@xxxxxxxxxxxxxxx
Signed-off-by: Len Brown <len.brown@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/power/x86/turbostat/turbostat.8 b/tools/power/x86/turbostat/turbostat.8
index 9b17097bc3d7b..b3d4bf08e70b1 100644
--- a/tools/power/x86/turbostat/turbostat.8
+++ b/tools/power/x86/turbostat/turbostat.8
@@ -296,6 +296,8 @@ 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 4f176bbf29f42..84b8a35c91972 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -5237,7 +5237,7 @@ 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;
}
