Avoid misdetecting FP16 compute support on Exynos 9810

3 files changed, 20 insertions, 12 deletions

diff --git a/src/arm/linux/aarch64-isa.c b/src/arm/linux/aarch64-isa.c
index aa40e4b..783b8e8 100644
--- a/src/arm/linux/aarch64-isa.c
+++ b/src/arm/linux/aarch64-isa.c
@@ -7,6 +7,7 @@
 void cpuinfo_arm64_linux_decode_isa_from_proc_cpuinfo(
 	uint32_t features,
 	uint32_t midr,
+	const struct cpuinfo_arm_chipset chipset[restrict static 1],
 	struct cpuinfo_arm_isa isa[restrict static 1])
 {
 	if (features & CPUINFO_ARM_LINUX_FEATURE_AES) {
@@ -29,7 +30,12 @@ void cpuinfo_arm64_linux_decode_isa_from_proc_cpuinfo(
 	}
 	const uint32_t fp16arith_mask = CPUINFO_ARM_LINUX_FEATURE_FPHP | CPUINFO_ARM_LINUX_FEATURE_ASIMDHP;
 	if ((features & fp16arith_mask) == fp16arith_mask) {
-		isa->fp16arith = true;
+		if (chipset->series == cpuinfo_arm_chipset_series_samsung_exynos && chipset->model == 9810) {
+			/* Exynos 9810 reports that it supports FP16 compute, but in fact only little cores do */
+			cpuinfo_log_warning("FP16 arithmetics disabled: only little cores of Exynos 9810 support FP16 compute");
+		} else {
+			isa->fp16arith = true;
+		}
 	} else if (features & CPUINFO_ARM_LINUX_FEATURE_FPHP) {
 		cpuinfo_log_warning("FP16 arithmetics disabled: detected support only for scalar operations");
 	} else if (features & CPUINFO_ARM_LINUX_FEATURE_ASIMDHP) {
diff --git a/src/arm/linux/api.h b/src/arm/linux/api.h
index 7599c2e..554a8b9 100644
--- a/src/arm/linux/api.h
+++ b/src/arm/linux/api.h
@@ -266,6 +266,7 @@ bool cpuinfo_arm_linux_parse_proc_cpuinfo(
 	void cpuinfo_arm64_linux_decode_isa_from_proc_cpuinfo(
 		uint32_t features,
 		uint32_t midr,
+		const struct cpuinfo_arm_chipset chipset[restrict static 1],
 		struct cpuinfo_arm_isa isa[restrict static 1]);
 #endif
 
diff --git a/src/arm/linux/init.c b/src/arm/linux/init.c
index 604dd27..27ae823 100644
--- a/src/arm/linux/init.c
+++ b/src/arm/linux/init.c
@@ -203,6 +203,16 @@ void cpuinfo_arm_linux_init(void) {
 		}
 	}
 
+#if defined(__ANDROID__)
+	const struct cpuinfo_arm_chipset chipset =
+		cpuinfo_arm_android_decode_chipset(&android_properties, usable_processors, 0);
+#else
+	const struct cpuinfo_arm_chipset chipset = {
+		.vendor = cpuinfo_arm_chipset_vendor_unknown,
+		.series = cpuinfo_arm_chipset_series_unknown,
+	};
+#endif
+
 	#if CPUINFO_ARCH_ARM
 		uint32_t isa_features = 0, isa_features2 = 0;
 		#ifdef __ANDROID__
@@ -248,7 +258,8 @@ void cpuinfo_arm_linux_init(void) {
 	#elif CPUINFO_ARCH_ARM64
 		/* getauxval is always available on ARM64 Android */
 		const uint32_t isa_features = cpuinfo_arm_linux_hwcap_from_getauxval();
-		cpuinfo_arm64_linux_decode_isa_from_proc_cpuinfo(isa_features, last_midr, &cpuinfo_isa);
+		cpuinfo_arm64_linux_decode_isa_from_proc_cpuinfo(
+			isa_features, last_midr, &chipset, &cpuinfo_isa);
 	#endif
 
 	/* Detect min/max frequency and package ID */
@@ -324,16 +335,6 @@ void cpuinfo_arm_linux_init(void) {
 
 	cpuinfo_arm_linux_count_cluster_processors(arm_linux_processors_count, arm_linux_processors);
 
-#if defined(__ANDROID__)
-	const struct cpuinfo_arm_chipset chipset =
-		cpuinfo_arm_android_decode_chipset(&android_properties, usable_processors, 0);
-#else
-	const struct cpuinfo_arm_chipset chipset = {
-		.vendor = cpuinfo_arm_chipset_vendor_unknown,
-		.series = cpuinfo_arm_chipset_series_unknown,
-	};
-#endif
-
 	const uint32_t cluster_count = cpuinfo_arm_linux_detect_cluster_midr(
 		&chipset,
 		arm_linux_processors_count, usable_processors, arm_linux_processors);