drivers/gpu/drm/nouveau/nouveau_acpi.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/nouveau/nouveau_acpi.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/nouveau/nouveau_acpi.c
Extension
.c
Size
10708 bytes
Lines
399
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

bool nouveau_is_optimus(void) {
	return nouveau_dsm_priv.optimus_detected;
}

bool nouveau_is_v1_dsm(void) {
	return nouveau_dsm_priv.dsm_detected;
}

#ifdef CONFIG_VGA_SWITCHEROO
static const guid_t nouveau_dsm_muid =
	GUID_INIT(0x9D95A0A0, 0x0060, 0x4D48,
		  0xB3, 0x4D, 0x7E, 0x5F, 0xEA, 0x12, 0x9F, 0xD4);

static const guid_t nouveau_op_dsm_muid =
	GUID_INIT(0xA486D8F8, 0x0BDA, 0x471B,
		  0xA7, 0x2B, 0x60, 0x42, 0xA6, 0xB5, 0xBE, 0xE0);

static int nouveau_optimus_dsm(acpi_handle handle, int func, int arg, uint32_t *result)
{
	int i;
	union acpi_object *obj;
	char args_buff[4];
	union acpi_object argv4 = {
		.buffer.type = ACPI_TYPE_BUFFER,
		.buffer.length = 4,
		.buffer.pointer = args_buff
	};

	/* ACPI is little endian, AABBCCDD becomes {DD,CC,BB,AA} */
	for (i = 0; i < 4; i++)
		args_buff[i] = (arg >> i * 8) & 0xFF;

	*result = 0;
	obj = acpi_evaluate_dsm_typed(handle, &nouveau_op_dsm_muid, 0x00000100,
				      func, &argv4, ACPI_TYPE_BUFFER);
	if (!obj) {
		acpi_handle_info(handle, "failed to evaluate _DSM\n");
		return AE_ERROR;
	} else {
		if (obj->buffer.length == 4) {
			*result |= obj->buffer.pointer[0];
			*result |= (obj->buffer.pointer[1] << 8);
			*result |= (obj->buffer.pointer[2] << 16);
			*result |= (obj->buffer.pointer[3] << 24);
		}
		ACPI_FREE(obj);
	}

	return 0;
}

/*
 * On some platforms, _DSM(nouveau_op_dsm_muid, func0) has special
 * requirements on the fourth parameter, so a private implementation
 * instead of using acpi_check_dsm().
 */
static int nouveau_dsm_get_optimus_functions(acpi_handle handle)
{
	int result;

	/*
	 * Function 0 returns a Buffer containing available functions.
	 * The args parameter is ignored for function 0, so just put 0 in it
	 */
	if (nouveau_optimus_dsm(handle, 0, 0, &result))
		return 0;

	/*
	 * ACPI Spec v4 9.14.1: if bit 0 is zero, no function is supported.
	 * If the n-th bit is enabled, function n is supported
	 */
	if (result & 1 && result & (1 << NOUVEAU_DSM_OPTIMUS_CAPS))
		return result;
	return 0;
}

static int nouveau_dsm(acpi_handle handle, int func, int arg)
{
	int ret = 0;
	union acpi_object *obj;
	union acpi_object argv4 = {
		.integer.type = ACPI_TYPE_INTEGER,
		.integer.value = arg,
	};

	obj = acpi_evaluate_dsm_typed(handle, &nouveau_dsm_muid, 0x00000102,
				      func, &argv4, ACPI_TYPE_INTEGER);
	if (!obj) {
		acpi_handle_info(handle, "failed to evaluate _DSM\n");
		return AE_ERROR;

Annotation

Implementation Notes