diff options
| -rw-r--r-- | src/soc/intel/common/block/graphics/Kconfig | 20 | ||||
| -rw-r--r-- | src/soc/intel/common/block/graphics/graphics.c | 22 |
2 files changed, 41 insertions, 1 deletions
diff --git a/src/soc/intel/common/block/graphics/Kconfig b/src/soc/intel/common/block/graphics/Kconfig index d586fd8ab8..30e4f8e800 100644 --- a/src/soc/intel/common/block/graphics/Kconfig +++ b/src/soc/intel/common/block/graphics/Kconfig @@ -37,4 +37,24 @@ config SOC_INTEL_GFX_NON_PREFETCHABLE_MMIO Ignore BAR0(offset 0x10)'s pre-fetchable attribute to use non-prefetchable MMIO to fix OS display driver failure. +config SOC_INTEL_GFX_MBUS_JOIN + bool + help + The MBUS (Memory Bus) is a high-speed interface that connects the graphics + controller to the system memory. It provides a dedicated data path for graphics + data, which helps to improve graphics performance. + + The MBUS is a key technology that helps to make the Intel i915 driver powerful + and versatile graphics drivers available. It provides the high-speed data transfer + capabilities that are essential for smooth and responsive graphics performance. + + Enable this config to ensure that the Intel GFX controller joins the MBUS before the + i915 driver is loaded. This is necessary to prevent the i915 driver from re-initializing + the display if the firmware has already initialized it. Without this config, the i915 + driver will initialize the display to bring up the login screen although the firmware + has initialized the display using the GFX MMIO registers and framebuffer. + + When enabled, saves 75ms-80ms of the boot time by avoiding redundent display + initialization by kernel graphics driver (i.e., i915_gfx). + endif diff --git a/src/soc/intel/common/block/graphics/graphics.c b/src/soc/intel/common/block/graphics/graphics.c index 9d541d0208..4bec7a4cc6 100644 --- a/src/soc/intel/common/block/graphics/graphics.c +++ b/src/soc/intel/common/block/graphics/graphics.c @@ -16,6 +16,11 @@ #include <soc/pci_devs.h> #include <types.h> +#define GFX_MBUS_CTL 0x4438C +#define GFX_MBUS_JOIN BIT(31) +#define GFX_MBUS_HASHING_MODE BIT(30) +#define GFX_MBUS_JOIN_PIPE_SEL (BIT(28) | BIT(27) | BIT(26)) + /* SoC Overrides */ __weak void graphics_soc_panel_init(struct device *dev) { @@ -256,12 +261,27 @@ static void graphics_dev_read_resources(struct device *dev) } } +static void graphics_dev_final(struct device *dev) +{ + pci_dev_request_bus_master(dev); + + if (CONFIG(SOC_INTEL_GFX_MBUS_JOIN)) { + uint32_t hashing_mode = 0; /* 2x2 */ + uint32_t pipe_select = 0; /* None */ + if (!get_external_display_status()) { + hashing_mode = GFX_MBUS_HASHING_MODE; /* 1x4 */ + pipe_select = GFX_MBUS_JOIN_PIPE_SEL; /* Pipe-A */ + } + graphics_gtt_rmw(GFX_MBUS_CTL, (uint32_t)(~pipe_select), GFX_MBUS_JOIN | hashing_mode); + } +} + const struct device_operations graphics_ops = { .read_resources = graphics_dev_read_resources, .set_resources = pci_dev_set_resources, .enable_resources = pci_dev_enable_resources, .init = gma_init, - .final = pci_dev_request_bus_master, + .final = graphics_dev_final, .ops_pci = &pci_dev_ops_pci, #if CONFIG(HAVE_ACPI_TABLES) .acpi_fill_ssdt = gma_generate_ssdt, |