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 struct intel_dsm_priv {
  16         acpi_handle dhandle;
  17 } intel_dsm_priv;
  18
  19 static const guid_t intel_dsm_guid =
  20         GUID_INIT(0x7ed873d3, 0xc2d0, 0x4e4f,
  21                   0xa8, 0x54, 0x0f, 0x13, 0x17, 0xb0, 0x1c, 0x2c);
  22
  23 static char *intel_dsm_port_name(u8 id)
  24 {
  25         switch (id) {
  26         case 0:
  27                 return "Reserved";
  28         case 1:
  29                 return "Analog VGA";
  30         case 2:
  31                 return "LVDS";
  32         case 3:
  33                 return "Reserved";
  34         case 4:
  35                 return "HDMI/DVI_B";
  36         case 5:
  37                 return "HDMI/DVI_C";
  38         case 6:
  39                 return "HDMI/DVI_D";
  40         case 7:
  41                 return "DisplayPort_A";
  42         case 8:
  43                 return "DisplayPort_B";
  44         case 9:
  45                 return "DisplayPort_C";
  46         case 0xa:
  47                 return "DisplayPort_D";
  48         case 0xb:
  49         case 0xc:
  50         case 0xd:
  51                 return "Reserved";
  52         case 0xe:
  53                 return "WiDi";
  54         default:
  55                 return "bad type";
  56         }
  57 }
  58
  59 static char *intel_dsm_mux_type(u8 type)
  60 {
  61         switch (type) {
  62         case 0:
  63                 return "unknown";
  64         case 1:
  65                 return "No MUX, iGPU only";
  66         case 2:
  67                 return "No MUX, dGPU only";
  68         case 3:
  69                 return "MUXed between iGPU and dGPU";
  70         default:
  71                 return "bad type";
  72         }
  73 }
  74
  75 static void intel_dsm_platform_mux_info(void)
  76 {
  77         int i;
  78         union acpi_object *pkg, *connector_count;
  79
  80         pkg = acpi_evaluate_dsm_typed(intel_dsm_priv.dhandle, &intel_dsm_guid,
  81                         INTEL_DSM_REVISION_ID, INTEL_DSM_FN_PLATFORM_MUX_INFO,
  82                         NULL, ACPI_TYPE_PACKAGE);
  83         if (!pkg) {
  84                 DRM_DEBUG_DRIVER("failed to evaluate _DSM\n");
  85                 return;
  86         }
  87
  88         connector_count = &pkg->package.elements[0];
  89         DRM_DEBUG_DRIVER("MUX info connectors: %lld\n",
  90                   (unsigned long long)connector_count->integer.value);
  91         for (i = 1; i < pkg->package.count; i++) {
  92                 union acpi_object *obj = &pkg->package.elements[i];
  93                 union acpi_object *connector_id = &obj->package.elements[0];
  94                 union acpi_object *info = &obj->package.elements[1];
  95                 DRM_DEBUG_DRIVER("Connector id: 0x%016llx\n",
  96                           (unsigned long long)connector_id->integer.value);
  97                 DRM_DEBUG_DRIVER("  port id: %s\n",
  98                        intel_dsm_port_name(info->buffer.pointer[0]));
  99                 DRM_DEBUG_DRIVER("  display mux info: %s\n",
 100                        intel_dsm_mux_type(info->buffer.pointer[1]));
 101                 DRM_DEBUG_DRIVER("  aux/dc mux info: %s\n",
 102                        intel_dsm_mux_type(info->buffer.pointer[2]));
 103                 DRM_DEBUG_DRIVER("  hpd mux info: %s\n",
 104                        intel_dsm_mux_type(info->buffer.pointer[3]));
 105         }
 106
 107         ACPI_FREE(pkg);
 108 }
 109
 110 static bool intel_dsm_pci_probe(struct pci_dev *pdev)
 111 {
 112         acpi_handle dhandle;
 113
 114         dhandle = ACPI_HANDLE(&pdev->dev);
 115         if (!dhandle)
 116                 return false;
 117
 118         if (!acpi_check_dsm(dhandle, &intel_dsm_guid, INTEL_DSM_REVISION_ID,
 119                             1 << INTEL_DSM_FN_PLATFORM_MUX_INFO)) {
 120                 DRM_DEBUG_KMS("no _DSM method for intel device\n");
 121                 return false;
 122         }
 123
 124         intel_dsm_priv.dhandle = dhandle;
 125         intel_dsm_platform_mux_info();
 126
 127         return true;
 128 }
 129
 130 static bool intel_dsm_detect(void)
 131 {
 132         char acpi_method_name[255] = { 0 };
 133         struct acpi_buffer buffer = {sizeof(acpi_method_name), acpi_method_name};
 134         struct pci_dev *pdev = NULL;
 135         bool has_dsm = false;
 136         int vga_count = 0;
 137
 138         while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev)) != NULL) {
 139                 vga_count++;
 140                 has_dsm |= intel_dsm_pci_probe(pdev);
 141         }
 142
 143         if (vga_count == 2 && has_dsm) {
 144                 acpi_get_name(intel_dsm_priv.dhandle, ACPI_FULL_PATHNAME, &buffer);
 145                 DRM_DEBUG_DRIVER("vga_switcheroo: detected DSM switching method %s handle\n",
 146                                  acpi_method_name);
 147                 return true;
 148         }
 149
 150         return false;
 151 }
 152
 153 void intel_register_dsm_handler(void)
 154 {
 155         if (!intel_dsm_detect())
 156                 return;
 157 }
 158
 159 void intel_unregister_dsm_handler(void)
 160 {
 161 }