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