diff options
| -rw-r--r-- | src/soc/intel/common/block/graphics/graphics.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/src/soc/intel/common/block/graphics/graphics.c b/src/soc/intel/common/block/graphics/graphics.c index 69754fdc93..5b2484a45f 100644 --- a/src/soc/intel/common/block/graphics/graphics.c +++ b/src/soc/intel/common/block/graphics/graphics.c @@ -31,6 +31,56 @@ intel_igd_get_controller_info(const struct device *device) return NULL; } +/* + * Transcoders contain the timing generators for eDP, DP, and HDMI interfaces. + * Intel transcoders are based on Quick Sync Video, which offloads video + * encoding and decoding tasks from the CPU to the GPU. + * + * On Intel silicon, there are four display pipes (DDI-A to DDI-D) that support + * blending, color adjustments, scaling, and dithering. + * + * From the display block diagram perspective, the front end of the display + * contains the pipes. The pipes connect to the transcoder. The transcoder + * (except for wireless) connects to the DDIs to drive the IO/PHY. + * + * This logic checks if the DDI-A port is attached to the transcoder and + * enabled (bit 27). Traditionally, the on-board display (eDP) is attached to DDI-A. + * If the above conditions is met, then the on-board display is present and enabled. + * + * On platforms without an on-board display (i.e., value at bits 27-30 is between 2-9), + * meaning that DDI-A (eDP) is not enabled. + * + * Additionally, if bits 27-30 are all set to 0, this means that no DDI ports + * are enabled, and there is no display. + * + * Consider external display is present and enabled, if eDP/DDI-A is not enabled + * and transcoder is attached to any DDI port (bits 27-30 are not zero). + */ +static int get_external_display_status(void) +{ + uint32_t ddi_func_ctrl = graphics_gtt_read(TRANS_DDI_FUNC_CTL_A); + ddi_func_ctrl &= TRANS_DDI_PORT_MASK; + + /* + * Check if transcoder is none or connected to DDI-A port (aka eDP). + * Report no external display in both cases. + */ + if (ddi_func_ctrl == TRANS_DDI_PORT_NONE) { + return 0; + } else { + if (ddi_func_ctrl == TRANS_DDI_SELECT_PORT(PORT_A)) + return 0; + else + return 1; + } +} + +/* Check and report if an external display is attached */ +int fsp_soc_report_external_display(void) +{ + return graphics_get_framebuffer_address() && get_external_display_status(); +} + static void gma_init(struct device *const dev) { intel_gma_init_igd_opregion(); |