platform/x86: hp-wmi: fix fan table parsing

For Victus S devices, the BIOS fan table header was being incorrectly
parsed as:
struct {
	u8 unknown;
	u8 num_entries;
}

The first field should be num_fans and the second should be unknown. It
is pure coincidence that interpreting an "unknown" field as "num_entries"
worked on multiple device, however for board 8D87 (in an upcoming patch),
this assumption fails, and the hp-wmi driver fails to load.

We fix this by correcting the header definition and compensating for
num_entries by parsing each entry of the fan table until an all-NULL row
is obtained, mirroring the behavior of OMEN Gaming Hub on Windows.

Fixes: 46be1453e6e6 ("platform/x86: hp-wmi: add manual fan control for Victus S models")
Signed-off-by: Krishna Chomal <krishna.chomal108@gmail.com>
Link: https://patch.msgid.link/20260410191039.125659-2-krishna.chomal108@gmail.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

diff --git a/drivers/platform/x86/hp/hp-wmi.c b/drivers/platform/x86/hp/hp-wmi.c
index 77913373ed089f8a23d0afd068c5b1c8ec8c5839..205a7bf4cbf76db78925b80ff53d4b7bb2212f79 100644 (file)
--- a/drivers/platform/x86/hp/hp-wmi.c
+++ b/drivers/platform/x86/hp/hp-wmi.c
@@ -469,14 +469,14 @@ struct hp_wmi_hwmon_priv {
 };
 
 struct victus_s_fan_table_header {
+       u8 num_fans;
        u8 unknown;
-       u8 num_entries;
 } __packed;
 
 struct victus_s_fan_table_entry {
        u8 cpu_rpm;
        u8 gpu_rpm;
-       u8 unknown;
+       u8 noise_db;
 } __packed;
 
 struct victus_s_fan_table {
@@ -2563,7 +2563,9 @@ static int hp_wmi_setup_fan_settings(struct hp_wmi_hwmon_priv *priv)
        u8 fan_data[128] = { 0 };
        struct victus_s_fan_table *fan_table;
        u8 min_rpm, max_rpm;
-       int gpu_delta, ret;
+       u8 cpu_rpm, gpu_rpm, noise_db;
+       int gpu_delta, i, num_entries, ret;
+       size_t header_size, entry_size;
 
        /* Default behaviour on hwmon init is automatic mode */
        priv->mode = PWM_MODE_AUTO;
@@ -2578,13 +2580,36 @@ static int hp_wmi_setup_fan_settings(struct hp_wmi_hwmon_priv *priv)
                return ret;
 
        fan_table = (struct victus_s_fan_table *)fan_data;
-       if (fan_table->header.num_entries == 0 ||
-           sizeof(struct victus_s_fan_table_header) +
-           sizeof(struct victus_s_fan_table_entry) * fan_table->header.num_entries > sizeof(fan_data))
+       if (fan_table->header.num_fans == 0)
+               return -EINVAL;
+
+       header_size = sizeof(struct victus_s_fan_table_header);
+       entry_size = sizeof(struct victus_s_fan_table_entry);
+       num_entries = (sizeof(fan_data) - header_size) / entry_size;
+       min_rpm = U8_MAX;
+       max_rpm = 0;
+
+       for (i = 0 ; i < num_entries ; i++) {
+               cpu_rpm = fan_table->entries[i].cpu_rpm;
+               gpu_rpm = fan_table->entries[i].gpu_rpm;
+               noise_db = fan_table->entries[i].noise_db;
+
+               /*
+                * On some devices, the fan table is truncated with an all-zero row,
+                * hence we stop parsing here.
+                */
+               if (cpu_rpm == 0 && gpu_rpm == 0 && noise_db == 0)
+                       break;
+
+               if (cpu_rpm < min_rpm)
+                       min_rpm = cpu_rpm;
+               if (cpu_rpm > max_rpm)
+                       max_rpm = cpu_rpm;
+       }
+
+       if (min_rpm == U8_MAX || max_rpm == 0)
                return -EINVAL;
 
-       min_rpm = fan_table->entries[0].cpu_rpm;
-       max_rpm = fan_table->entries[fan_table->header.num_entries - 1].cpu_rpm;
        gpu_delta = fan_table->entries[0].gpu_rpm - fan_table->entries[0].cpu_rpm;
        priv->min_rpm = min_rpm;
        priv->max_rpm = max_rpm;