diff options
| -rw-r--r-- | src/soc/intel/broadwell/smihandler.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/src/soc/intel/broadwell/smihandler.c b/src/soc/intel/broadwell/smihandler.c index 5004a6a214..63c93739e7 100644 --- a/src/soc/intel/broadwell/smihandler.c +++ b/src/soc/intel/broadwell/smihandler.c @@ -36,6 +36,7 @@ #include <soc/rcba.h> #include <soc/smm.h> #include <soc/xhci.h> +#include <drivers/intel/gma/i915_reg.h> static u8 smm_initialized = 0; @@ -109,6 +110,45 @@ static void busmaster_disable_on_bus(int bus) } } +/* + * Turn off the backlight if it is on, and wait for the specified + * backlight off delay. This will allow panel power timings to meet + * spec and prevent brief garbage on the screen when turned off + * during firmware with power button triggered SMI. + */ +static void backlight_off(void) +{ + void *reg_base; + uint32_t pp_ctrl; + uint32_t bl_off_delay; + + reg_base = (void *)((uintptr_t)pci_read_config32(SA_DEV_IGD, PCI_BASE_ADDRESS_0) & ~0xf); + + /* Check if backlight is enabled */ + pp_ctrl = read32(reg_base + PCH_PP_CONTROL); + if (!(pp_ctrl & EDP_BLC_ENABLE)) + return; + + /* Enable writes to this register */ + pp_ctrl &= ~PANEL_UNLOCK_MASK; + pp_ctrl |= PANEL_UNLOCK_REGS; + + /* Turn off backlight */ + pp_ctrl &= ~EDP_BLC_ENABLE; + + write32(reg_base + PCH_PP_CONTROL, pp_ctrl); + read32(reg_base + PCH_PP_CONTROL); + + /* Read backlight off delay in 100us units */ + bl_off_delay = read32(reg_base + PCH_PP_OFF_DELAYS); + bl_off_delay &= PANEL_LIGHT_OFF_DELAY_MASK; + bl_off_delay *= 100; + + /* Wait for backlight to turn off */ + udelay(bl_off_delay); + + printk(BIOS_INFO, "Backlight turned off\n"); +} static void southbridge_smi_sleep(void) { @@ -170,6 +210,9 @@ static void southbridge_smi_sleep(void) case SLP_TYP_S5: printk(BIOS_DEBUG, "SMI#: Entering S5 (Soft Power off)\n"); + /* Turn off backlight if needed */ + backlight_off(); + /* Disable all GPE */ disable_all_gpe(); |