From: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

[ Upstream commit b6398bc2ef3a78f1be37ba01ae0a5eedaee47803 ]

Problem: individual swidle counter names (C1, C1+, C1-, etc.) cannot be
selected via --show/--hide due to two bugs in probe_cpuidle_counts():
1. The function returns immediately when BIC_cpuidle is not enabled,
   without checking deferred_add_index.
2. The deferred name check runs against name_buf before the trailing
   newline is stripped, so is_deferred_add("C1\n") never matches "C1".

Fix:
1. Relax the early return to pass through when deferred names are
   queued.
2. Strip the trailing newline from name_buf before performing deferred
   name checks.
3. Check each suffixed variant (C1+, C1, C1-) individually so that
   e.g. "--show C1+" enables only the requested metric.

In addition, introduce a helper function to avoid repeating the
condition (readability cleanup).

Fixes: ec4acd3166d8 ("tools/power turbostat: disable "cpuidle" invocation counters, by default")
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

LLM Generated explanations, may be completely bogus:

Error: Failed to generate final synthesis

 tools/power/x86/turbostat/turbostat.c | 35 ++++++++++++++++-----------
 1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 67dfd3eaad014..48677f1846347 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -10890,6 +10890,14 @@ void probe_cpuidle_residency(void)
 	}
 }
 
+static bool cpuidle_counter_wanted(char *name)
+{
+	if (is_deferred_skip(name))
+		return false;
+
+	return DO_BIC(BIC_cpuidle) || is_deferred_add(name);
+}
+
 void probe_cpuidle_counts(void)
 {
 	char path[64];
@@ -10899,7 +10907,7 @@ void probe_cpuidle_counts(void)
 	int min_state = 1024, max_state = 0;
 	char *sp;
 
-	if (!DO_BIC(BIC_cpuidle))
+	if (!DO_BIC(BIC_cpuidle) && !deferred_add_index)
 		return;
 
 	for (state = 10; state >= 0; --state) {
@@ -10914,12 +10922,6 @@ void probe_cpuidle_counts(void)
 
 		remove_underbar(name_buf);
 
-		if (!DO_BIC(BIC_cpuidle) && !is_deferred_add(name_buf))
-			continue;
-
-		if (is_deferred_skip(name_buf))
-			continue;
-
 		/* truncate "C1-HSW\n" to "C1", or truncate "C1\n" to "C1" */
 		sp = strchr(name_buf, '-');
 		if (!sp)
@@ -10934,16 +10936,19 @@ void probe_cpuidle_counts(void)
 			 * Add 'C1+' for C1, and so on. The 'below' sysfs file always contains 0 for
 			 * the last state, so do not add it.
 			 */
-
 			*sp = '+';
 			*(sp + 1) = '\0';
-			sprintf(path, "cpuidle/state%d/below", state);
-			add_counter(0, path, name_buf, 64, SCOPE_CPU, COUNTER_ITEMS, FORMAT_DELTA, SYSFS_PERCPU, 0);
+			if (cpuidle_counter_wanted(name_buf)) {
+				sprintf(path, "cpuidle/state%d/below", state);
+				add_counter(0, path, name_buf, 64, SCOPE_CPU, COUNTER_ITEMS, FORMAT_DELTA, SYSFS_PERCPU, 0);
+			}
 		}
 
 		*sp = '\0';
-		sprintf(path, "cpuidle/state%d/usage", state);
-		add_counter(0, path, name_buf, 64, SCOPE_CPU, COUNTER_ITEMS, FORMAT_DELTA, SYSFS_PERCPU, 0);
+		if (cpuidle_counter_wanted(name_buf)) {
+			sprintf(path, "cpuidle/state%d/usage", state);
+			add_counter(0, path, name_buf, 64, SCOPE_CPU, COUNTER_ITEMS, FORMAT_DELTA, SYSFS_PERCPU, 0);
+		}
 
 		/*
 		 * The 'above' sysfs file always contains 0 for the shallowest state (smallest
@@ -10952,8 +10957,10 @@ void probe_cpuidle_counts(void)
 		if (state != min_state) {
 			*sp = '-';
 			*(sp + 1) = '\0';
-			sprintf(path, "cpuidle/state%d/above", state);
-			add_counter(0, path, name_buf, 64, SCOPE_CPU, COUNTER_ITEMS, FORMAT_DELTA, SYSFS_PERCPU, 0);
+			if (cpuidle_counter_wanted(name_buf)) {
+				sprintf(path, "cpuidle/state%d/above", state);
+				add_counter(0, path, name_buf, 64, SCOPE_CPU, COUNTER_ITEMS, FORMAT_DELTA, SYSFS_PERCPU, 0);
+			}
 		}
 	}
 }
-- 
2.53.0