drivers/gpu/drm/i915/intel_acpi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Intel ACPI functions
   4  *
   5  * _DSM related code stolen from nouveau_acpi.c.
   6  */
   7 #include <linux/pci.h>
   8 #include <linux/acpi.h>
   9 #include "i915_drv.h"
  10
  11 #define INTEL_DSM_REVISION_ID 1 /* For Calpella anyway... */
  12 #define INTEL_DSM_FN_PLATFORM_MUX_INFO 1 /* No args */
  13
  14 static const guid_t intel_dsm_guid =
  15         GUID_INIT(0x7ed873d3, 0xc2d0, 0x4e4f,
  16                   0xa8, 0x54, 0x0f, 0x13, 0x17, 0xb0, 0x1c, 0x2c);
  17
  18 static char *intel_dsm_port_name(u8 id)
  19 {
  20         switch (id) {
  21         case 0:
  22                 return "Reserved";
  23         case 1:
  24                 return "Analog VGA";
  25         case 2:
  26                 return "LVDS";
  27         case 3:
  28                 return "Reserved";
  29         case 4:
  30                 return "HDMI/DVI_B";
  31         case 5:
  32                 return "HDMI/DVI_C";
  33         case 6:
  34                 return "HDMI/DVI_D";
  35         case 7:
  36                 return "DisplayPort_A";
  37         case 8:
  38                 return "DisplayPort_B";
  39         case 9:
  40                 return "DisplayPort_C";
  41         case 0xa:
  42                 return "DisplayPort_D";
  43         case 0xb:
  44         case 0xc:
  45         case 0xd:
  46                 return "Reserved";
  47         case 0xe:
  48                 return "WiDi";
  49         default:
  50                 return "bad type";
  51         }
  52 }
  53
  54 static char *intel_dsm_mux_type(u8 type)
  55 {
  56         switch (type) {
  57         case 0:
  58                 return "unknown";
  59         case 1:
  60                 return "No MUX, iGPU only";
  61         case 2:
  62                 return "No MUX, dGPU only";
  63         case 3:
  64                 return "MUXed between iGPU and dGPU";
  65         default:
  66                 return "bad type";
  67         }
  68 }
  69
  70 static void intel_dsm_platform_mux_info(acpi_handle dhandle)
  71 {
  72         int i;
  73         union acpi_object *pkg, *connector_count;
  74
  75         pkg = acpi_evaluate_dsm_typed(dhandle, &intel_dsm_guid,
  76                         INTEL_DSM_REVISION_ID, INTEL_DSM_FN_PLATFORM_MUX_INFO,
  77                         NULL, ACPI_TYPE_PACKAGE);
  78         if (!pkg) {
  79                 DRM_DEBUG_DRIVER("failed to evaluate _DSM\n");
  80                 return;
  81         }
  82
  83         connector_count = &pkg->package.elements[0];
  84         DRM_DEBUG_DRIVER("MUX info connectors: %lld\n",
  85                   (unsigned long long)connector_count->integer.value);
  86         for (i = 1; i < pkg->package.count; i++) {
  87                 union acpi_object *obj = &pkg->package.elements[i];
  88                 union acpi_object *connector_id = &obj->package.elements[0];
  89                 union acpi_object *info = &obj->package.elements[1];
  90                 DRM_DEBUG_DRIVER("Connector id: 0x%016llx\n",
  91                           (unsigned long long)connector_id->integer.value);
  92                 DRM_DEBUG_DRIVER("  port id: %s\n",
  93                        intel_dsm_port_name(info->buffer.pointer[0]));
  94                 DRM_DEBUG_DRIVER("  display mux info: %s\n",
  95                        intel_dsm_mux_type(info->buffer.pointer[1]));
  96                 DRM_DEBUG_DRIVER("  aux/dc mux info: %s\n",
  97                        intel_dsm_mux_type(info->buffer.pointer[2]));
  98                 DRM_DEBUG_DRIVER("  hpd mux info: %s\n",
  99                        intel_dsm_mux_type(info->buffer.pointer[3]));
 100         }
 101
 102         ACPI_FREE(pkg);
 103 }
 104
 105 static acpi_handle intel_dsm_pci_probe(struct pci_dev *pdev)
 106 {
 107         acpi_handle dhandle;
 108
 109         dhandle = ACPI_HANDLE(&pdev->dev);
 110         if (!dhandle)
 111                 return NULL;
 112
 113         if (!acpi_check_dsm(dhandle, &intel_dsm_guid, INTEL_DSM_REVISION_ID,
 114                             1 << INTEL_DSM_FN_PLATFORM_MUX_INFO)) {
 115                 DRM_DEBUG_KMS("no _DSM method for intel device\n");
 116                 return NULL;
 117         }
 118
 119         intel_dsm_platform_mux_info(dhandle);
 120
 121         return dhandle;
 122 }
 123
 124 static bool intel_dsm_detect(void)
 125 {
 126         acpi_handle dhandle = NULL;
 127         char acpi_method_name[255] = { 0 };
 128         struct acpi_buffer buffer = {sizeof(acpi_method_name), acpi_method_name};
 129         struct pci_dev *pdev = NULL;
 130         int vga_count = 0;
 131
 132         while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev)) != NULL) {
 133                 vga_count++;
 134                 dhandle = intel_dsm_pci_probe(pdev) ?: dhandle;
 135         }
 136
 137         if (vga_count == 2 && dhandle) {
 138                 acpi_get_name(dhandle, ACPI_FULL_PATHNAME, &buffer);
 139                 DRM_DEBUG_DRIVER("vga_switcheroo: detected DSM switching method %s handle\n",
 140                                  acpi_method_name);
 141                 return true;
 142         }
 143
 144         return false;
 145 }
 146
 147 void intel_register_dsm_handler(void)
 148 {
 149         if (!intel_dsm_detect())
 150                 return;
 151 }
 152
 153 void intel_unregister_dsm_handler(void)
 154 {
 155 }