platform/x86: think-lmi: Add possible_values for ThinkStation

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.

Fixes: a40cd7ef22fb ("platform/x86: think-lmi: Add WMI interface support on Lenovo platforms")
Signed-off-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Link: https://lore.kernel.org/r/20230320003221.561750-4-mpearson-lenovo@squebb.ca
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
index 3f06413..c816646 100644 (file)
--- a/drivers/platform/x86/think-lmi.c
+++ b/drivers/platform/x86/think-lmi.c
@@ -1450,6 +1450,26 @@ 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);
+                               }
+                       }
                }
                /*
                 * firmware-attributes requires that possible_values are separated by ';' but