Re: [PATCH v2 05/10] platform/x86: alienware-wmi-wmax: Improve platform profile probe

Kurt Borja
2025-03-04T16:22:06Z

On Tue Mar 4, 2025 at 10:40 AM -05, Ilpo Järvinen wrote:
> On Tue, 25 Feb 2025, Kurt Borja wrote:
>
>> Get and store the AWCC system description in alienware_awcc_setup()
>> instead of awcc_platform_profile_probe() and add a check for integer
>> overflows to avoid misbehaviors.
>>
>> While at it, replace set_bit() with it's non-atomic version __set_bit()
>> because `choices` belong to this thread only.
>>
>> Signed-off-by: Kurt Borja <kuurtb@gmail.com>
>> Reviewed-by: Armin Wolf <W_Armin@gmx.de>
>> ---
>> .../platform/x86/dell/alienware-wmi-wmax.c | 61 ++++++++++++++-----
>> 1 file changed, 46 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/platform/x86/dell/alienware-wmi-wmax.c b/drivers/platform/x86/dell/alienware-wmi-wmax.c
>> index 4a8335d90b5d..965b427f8f0a 100644
>> --- a/drivers/platform/x86/dell/alienware-wmi-wmax.c
>> +++ b/drivers/platform/x86/dell/alienware-wmi-wmax.c
>> @@ -37,6 +37,9 @@
>> #define AWCC_THERMAL_MODE_MASK GENMASK(3, 0)
>> #define AWCC_RESOURCE_ID_MASK GENMASK(7, 0)
>>
>> +/* Arbitrary limit based on supported models */
>> +#define AWCC_MAX_RES_COUNT 16
>> +
>> static bool force_platform_profile;
>> module_param_unsafe(force_platform_profile, bool, 0);
>> MODULE_PARM_DESC(force_platform_profile, "Forces auto-detecting thermal profiles without checking if WMI thermal backend is available");
>> @@ -211,6 +214,17 @@ struct wmax_u32_args {
>>
>> struct awcc_priv {
>> struct wmi_device *wdev;
>> + union {
>> + u32 system_description;
>> + struct {
>> + u8 fan_count;
>> + u8 temp_count;
>> + u8 unknown_count;
>> + u8 profile_count;
>> + } __packed;
>> + u8 res_count[4];
>> + } __packed;
>
> I don't like it how __packed is now creeping its way into priv structure
> too. It doesn't even seem useful in this case as all those are naturally
> aligned and take 4 bytes, AFAICT. Why did you add it?

You are right, I think alignment here is already guaranteed. Alignment
is still a bit confusing for me.

I'll drop it for v3.

--
~ Kurt

>
>> +
>> struct device *ppdev;
>> u8 supported_profiles[PLATFORM_PROFILE_LAST];
>> };
>> @@ -614,38 +628,41 @@ static int awcc_platform_profile_probe(void *drvdata, unsigned long *choices)
>> enum platform_profile_option profile;
>> struct awcc_priv *priv = drvdata;
>> enum awcc_thermal_profile mode;
>> - u8 sys_desc[4];
>> - u32 first_mode;
>> + u8 id, offset = 0;
>> u32 out_data;
>> int ret;
>> - u8 id;
>>
>> - ret = awcc_thermal_information(priv->wdev, AWCC_OP_GET_SYSTEM_DESCRIPTION,
>> - 0, (u32 *) &sys_desc);
>> - if (ret < 0)
>> - return ret;
>> -
>> - first_mode = sys_desc[0] + sys_desc[1];
>> -
>> - for (u32 i = 0; i < sys_desc[3]; i++) {
>> - ret = awcc_op_get_resource_id(priv->wdev, i + first_mode, &out_data);
>> + /*
>> + * Thermal profile IDs are listed last at offset
>> + * fan_count + temp_count + unknown_count
>> + */
>> + for (unsigned int i = 0; i < ARRAY_SIZE(priv->res_count) - 1; i++)
>> + offset += priv->res_count[i];
>>
>> + for (unsigned int i = 0; i < priv->profile_count; i++) {
>> + ret = awcc_op_get_resource_id(priv->wdev, i + offset, &out_data);
>> if (ret == -EIO)
>> return ret;
>>
>> + /*
>> + * Some devices report an incorrect number of thermal profiles
>> + * so the resource ID list may end prematurely
>> + */
>> if (ret == -EBADRQC)
>> break;
>>
>> /* Some IDs have a BIT(8) flag that should be ignored */
>> id = FIELD_GET(AWCC_RESOURCE_ID_MASK, out_data);
>> - if (!is_awcc_thermal_profile_id(id))
>> + if (!is_awcc_thermal_profile_id(id)) {
>> + dev_dbg(&priv->wdev->dev, "Unmapped thermal profile ID 0x%02x\n", id);
>> continue;
>> + }
>>
>> mode = FIELD_GET(AWCC_THERMAL_MODE_MASK, id);
>> profile = awcc_mode_to_platform_profile[mode];
>> priv->supported_profiles[profile] = id;
>>
>> - set_bit(profile, choices);
>> + __set_bit(profile, choices);
>> }
>>
>> if (bitmap_empty(choices, PLATFORM_PROFILE_LAST))
>> @@ -655,7 +672,7 @@ static int awcc_platform_profile_probe(void *drvdata, unsigned long *choices)
>> priv->supported_profiles[PLATFORM_PROFILE_PERFORMANCE] =
>> AWCC_THERMAL_MODE_GMODE;
>>
>> - set_bit(PLATFORM_PROFILE_PERFORMANCE, choices);
>> + __set_bit(PLATFORM_PROFILE_PERFORMANCE, choices);
>> }
>>
>> return 0;
>> @@ -686,6 +703,20 @@ static int alienware_awcc_setup(struct wmi_device *wdev)
>> if (!priv)
>> return -ENOMEM;
>>
>> + ret = awcc_thermal_information(wdev, AWCC_OP_GET_SYSTEM_DESCRIPTION,
>> + 0, &priv->system_description);
>> + if (ret < 0)
>> + return ret;
>> +
>> + /* Sanity check */
>> + for (unsigned int i = 0; i < ARRAY_SIZE(priv->res_count); i++) {
>> + if (priv->res_count[i] > AWCC_MAX_RES_COUNT) {
>> + dev_err(&wdev->dev, "Malformed system description: 0x%08x\n",
>> + priv->system_description);
>> + return -ENXIO;
>> + }
>> + }
>> +
>> priv->wdev = wdev;
>> dev_set_drvdata(&wdev->dev, priv);
>>
>>