drivers/gpu/drm/i915/display/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
   8 #include <linux/pci.h>
   9 #include <linux/acpi.h>
  10
  11 #include "i915_drv.h"
  12 #include "intel_acpi.h"
  13
  14 #define INTEL_DSM_REVISION_ID 1 /* For Calpella anyway... */
  15 #define INTEL_DSM_FN_PLATFORM_MUX_INFO 1 /* No args */
  16
  17 static const guid_t intel_dsm_guid =
  18         GUID_INIT(0x7ed873d3, 0xc2d0, 0x4e4f,
  19                   0xa8, 0x54, 0x0f, 0x13, 0x17, 0xb0, 0x1c, 0x2c);
  20
  21 static char *intel_dsm_port_name(u8 id)
  22 {
  23         switch (id) {
  24         case 0:
  25                 return "Reserved";
  26         case 1:
  27                 return "Analog VGA";
  28         case 2:
  29                 return "LVDS";
  30         case 3:
  31                 return "Reserved";
  32         case 4:
  33                 return "HDMI/DVI_B";
  34         case 5:
  35                 return "HDMI/DVI_C";
  36         case 6:
  37                 return "HDMI/DVI_D";
  38         case 7:
  39                 return "DisplayPort_A";
  40         case 8:
  41                 return "DisplayPort_B";
  42         case 9:
  43                 return "DisplayPort_C";
  44         case 0xa:
  45                 return "DisplayPort_D";
  46         case 0xb:
  47         case 0xc:
  48         case 0xd:
  49                 return "Reserved";
  50         case 0xe:
  51                 return "WiDi";
  52         default:
  53                 return "bad type";
  54         }
  55 }
  56
  57 static char *intel_dsm_mux_type(u8 type)
  58 {
  59         switch (type) {
  60         case 0:
  61                 return "unknown";
  62         case 1:
  63                 return "No MUX, iGPU only";
  64         case 2:
  65                 return "No MUX, dGPU only";
  66         case 3:
  67                 return "MUXed between iGPU and dGPU";
  68         default:
  69                 return "bad type";
  70         }
  71 }
  72
  73 static void intel_dsm_platform_mux_info(acpi_handle dhandle)
  74 {
  75         int i;
  76         union acpi_object *pkg, *connector_count;
  77
  78         pkg = acpi_evaluate_dsm_typed(dhandle, &intel_dsm_guid,
  79                         INTEL_DSM_REVISION_ID, INTEL_DSM_FN_PLATFORM_MUX_INFO,
  80                         NULL, ACPI_TYPE_PACKAGE);
  81         if (!pkg) {
  82                 DRM_DEBUG_DRIVER("failed to evaluate _DSM\n");
  83                 return;
  84         }
  85
  86         connector_count = &pkg->package.elements[0];
  87         DRM_DEBUG_DRIVER("MUX info connectors: %lld\n",
  88                   (unsigned long long)connector_count->integer.value);
  89         for (i = 1; i < pkg->package.count; i++) {
  90                 union acpi_object *obj = &pkg->package.elements[i];
  91                 union acpi_object *connector_id = &obj->package.elements[0];
  92                 union acpi_object *info = &obj->package.elements[1];
  93                 DRM_DEBUG_DRIVER("Connector id: 0x%016llx\n",
  94                           (unsigned long long)connector_id->integer.value);
  95                 DRM_DEBUG_DRIVER("  port id: %s\n",
  96                        intel_dsm_port_name(info->buffer.pointer[0]));
  97                 DRM_DEBUG_DRIVER("  display mux info: %s\n",
  98                        intel_dsm_mux_type(info->buffer.pointer[1]));
  99                 DRM_DEBUG_DRIVER("  aux/dc mux info: %s\n",
 100                        intel_dsm_mux_type(info->buffer.pointer[2]));
 101                 DRM_DEBUG_DRIVER("  hpd mux info: %s\n",
 102                        intel_dsm_mux_type(info->buffer.pointer[3]));
 103         }
 104
 105         ACPI_FREE(pkg);
 106 }
 107
 108 static acpi_handle intel_dsm_pci_probe(struct pci_dev *pdev)
 109 {
 110         acpi_handle dhandle;
 111
 112         dhandle = ACPI_HANDLE(&pdev->dev);
 113         if (!dhandle)
 114                 return NULL;
 115
 116         if (!acpi_check_dsm(dhandle, &intel_dsm_guid, INTEL_DSM_REVISION_ID,
 117                             1 << INTEL_DSM_FN_PLATFORM_MUX_INFO)) {
 118                 DRM_DEBUG_KMS("no _DSM method for intel device\n");
 119                 return NULL;
 120         }
 121
 122         intel_dsm_platform_mux_info(dhandle);
 123
 124         return dhandle;
 125 }
 126
 127 static bool intel_dsm_detect(void)
 128 {
 129         acpi_handle dhandle = NULL;
 130         char acpi_method_name[255] = { 0 };
 131         struct acpi_buffer buffer = {sizeof(acpi_method_name), acpi_method_name};
 132         struct pci_dev *pdev = NULL;
 133         int vga_count = 0;
 134
 135         while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev)) != NULL) {
 136                 vga_count++;
 137                 dhandle = intel_dsm_pci_probe(pdev) ?: dhandle;
 138         }
 139
 140         if (vga_count == 2 && dhandle) {
 141                 acpi_get_name(dhandle, ACPI_FULL_PATHNAME, &buffer);
 142                 DRM_DEBUG_DRIVER("vga_switcheroo: detected DSM switching method %s handle\n",
 143                                  acpi_method_name);
 144                 return true;
 145         }
 146
 147         return false;
 148 }
 149
 150 void intel_register_dsm_handler(void)
 151 {
 152         if (!intel_dsm_detect())
 153                 return;
 154 }
 155
 156 void intel_unregister_dsm_handler(void)
 157 {
 158 }