On Sat, Mar 18, 2023, at 12:35 PM, Thomas Weißschuh wrote:
> Hi Mark,
>
> please also CC linux-kernel@xxxxxxxxxxxxxxx and previous reviewers.
My apologies on previous reviewers - that was a miss on my behalf
I've never cc'd linux-kernel previously - is that a requirement? It's new to me if it is - what's the reason? (that mailing list seems unusable to me from my limited experience...)
Mark
>
> On Fri, Mar 17, 2023 at 11:46:34AM -0400, Mark Pearson wrote:
>> ThinkStation platforms don't support the API to return possible_values
>> but instead embed it in the settings string.
>>
>> Try and extract this information and set the possible_values attribute
>> appropriately.
>>
>> If there aren't any values possible then don't display possible_values.
>>
>> Signed-off-by: Mark Pearson <mpearson-lenovo@xxxxxxxxx>
>> ---
>> Changes in V3:
>> - Use is_visible attribute to determine if possible_values should be
>> available
>> - Code got refactored a bit to make compilation cleaner
>> Changes in V2:
>> - Move no value for possible_values handling into show function
>> - use kstrndup for allocating string
>>
>> drivers/platform/x86/think-lmi.c | 82 ++++++++++++++++++++++----------
>> 1 file changed, 56 insertions(+), 26 deletions(-)
>>
>> diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
>> index 5fa5451c4802..d89a1c9bdbf1 100644
>> --- a/drivers/platform/x86/think-lmi.c
>> +++ b/drivers/platform/x86/think-lmi.c
>> @@ -917,6 +917,8 @@ static ssize_t display_name_show(struct kobject *kobj, struct kobj_attribute *at
>> return sysfs_emit(buf, "%s\n", setting->display_name);
>> }
>>
>> +static struct kobj_attribute attr_displ_name = __ATTR_RO(display_name);
>> +
>> static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
>> {
>> struct tlmi_attr_setting *setting = to_tlmi_attr_setting(kobj);
>> @@ -937,30 +939,6 @@ static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *a
>> return ret;
>> }
>>
>> -static ssize_t possible_values_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
>> -{
>> - struct tlmi_attr_setting *setting = to_tlmi_attr_setting(kobj);
>> -
>> - if (!tlmi_priv.can_get_bios_selections)
>> - return -EOPNOTSUPP;
>> -
>> - return sysfs_emit(buf, "%s\n", setting->possible_values);
>> -}
>> -
>> -static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr,
>> - char *buf)
>> -{
>> - struct tlmi_attr_setting *setting = to_tlmi_attr_setting(kobj);
>> -
>> - if (setting->possible_values) {
>> - /* Figure out what setting type is as BIOS does not return this */
>> - if (strchr(setting->possible_values, ','))
>> - return sysfs_emit(buf, "enumeration\n");
>> - }
>> - /* Anything else is going to be a string */
>> - return sysfs_emit(buf, "string\n");
>> -}
>> -
>> static ssize_t current_value_store(struct kobject *kobj,
>> struct kobj_attribute *attr,
>> const char *buf, size_t count)
>> @@ -1044,14 +1022,46 @@ static ssize_t current_value_store(struct kobject *kobj,
>> return ret ?: count;
>> }
>>
>> -static struct kobj_attribute attr_displ_name = __ATTR_RO(display_name);
>> +static struct kobj_attribute attr_current_val = __ATTR_RW_MODE(current_value, 0600);
>> +
>> +static ssize_t possible_values_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
>> +{
>> + struct tlmi_attr_setting *setting = to_tlmi_attr_setting(kobj);
>> +
>> + return sysfs_emit(buf, "%s\n", setting->possible_values);
>> +}
>>
>> static struct kobj_attribute attr_possible_values = __ATTR_RO(possible_values);
>>
>> -static struct kobj_attribute attr_current_val = __ATTR_RW_MODE(current_value, 0600);
>> +static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr,
>> + char *buf)
>> +{
>> + struct tlmi_attr_setting *setting = to_tlmi_attr_setting(kobj);
>> +
>> + if (setting->possible_values) {
>> + /* Figure out what setting type is as BIOS does not return this */
>> + if (strchr(setting->possible_values, ','))
>> + return sysfs_emit(buf, "enumeration\n");
>> + }
>> + /* Anything else is going to be a string */
>> + return sysfs_emit(buf, "string\n");
>> +}
>
> This patch seems to introduce a lot of churn, is it intentional?
>>
>> static struct kobj_attribute attr_type = __ATTR_RO(type);
>>
>> +static umode_t attr_is_visible(struct kobject *kobj,
>> + struct attribute *attr, int n)
>> +{
>> + struct tlmi_attr_setting *setting = to_tlmi_attr_setting(kobj);
>> +
>> + /* We don't want to display possible_values attributes if not available */
>> + if (attr == (struct attribute *)&attr_possible_values)
>
> This cast is unsafe, if the struct kobj_attribute order is randomised it
> will break.
>
> You can use
>
> if (attr == &attr_possible_values.attr)
>
>> + if (!setting->possible_values)
>> + return 0;
>> +
>> + return attr->mode;
>> +}
>> +
>> static struct attribute *tlmi_attrs[] = {
>> &attr_displ_name.attr,
>> &attr_current_val.attr,
>> @@ -1061,6 +1071,7 @@ static struct attribute *tlmi_attrs[] = {
>> };
>>
>> static const struct attribute_group tlmi_attr_group = {
>> + .is_visible = attr_is_visible,
>> .attrs = tlmi_attrs,
>> };
>>
>> @@ -1440,6 +1451,25 @@ static int tlmi_analyze(void)
>> if (ret || !setting->possible_values)
>> pr_info("Error retrieving possible values for %d : %s\n",
>> i, setting->display_name);
>> + } else {
>> + /*
>> + * Older Thinkstations don't support the bios_selections API.
>> + * Instead they store this as a [Optional:Option1,Option2] section of the
>> + * name string.
>> + * Try and pull that out if it's available.
>> + */
>> + char *item, *optstart, *optend;
>> +
>> + if (!tlmi_setting(setting->index, &item, LENOVO_BIOS_SETTING_GUID)) {
>> + optstart = strstr(item, "[Optional:");
>> + if (optstart) {
>> + optstart += strlen("[Optional:");
>> + optend = strstr(optstart, "]");
>> + if (optend)
>> + setting->possible_values =
>> + kstrndup(optstart, optend - optstart, GFP_KERNEL);
>> + }
>> + }
>
> The patch now does two things:
> 1) Hide the sysfs attributes if the value is not available
> 2) Extract the value from the description
>
> Maybe it could be split in two?
>
> Another observation:
> Would it make sense to remove the part
> "[Optional:Option1,Option2]" from the name attribute?
>
>> }
>> kobject_init(&setting->kobj, &tlmi_attr_setting_ktype);
>> tlmi_priv.setting[i] = setting;
>> --
>> 2.39.2
>>
