On T2 Macs with MMIO gmux, when GMUX_PORT_SWITCH_DISPLAY is read, it can have values of 2, 3, 4, and 5. Odd values correspond to the discrete gpu, and even values correspond to the integrated gpu. The current logic is that only 2 corresponds to IGD, but this doesn't work for T2 Macs. Instead, check the first bit to determine the connected gpu. As T2 Macs with gmux only can switch the internal display, it is untested if this change (or a similar change) would be applicable to GMUX_PORT_SWITCH_DDC and GMUX_PORT_SWITCH_EXTERNAL. Signed-off-by: Orlando Chamberlain <orlandoch.dev@xxxxxxxxx> --- v1->v2: no change drivers/platform/x86/apple-gmux.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c index 9333f82cfa8a..ec99e05e532c 100644 --- a/drivers/platform/x86/apple-gmux.c +++ b/drivers/platform/x86/apple-gmux.c @@ -346,10 +346,10 @@ static void gmux_read_switch_state(struct apple_gmux_data *gmux_data) else gmux_data->switch_state_ddc = VGA_SWITCHEROO_DIS; - if (gmux_read8(gmux_data, GMUX_PORT_SWITCH_DISPLAY) == 2) - gmux_data->switch_state_display = VGA_SWITCHEROO_IGD; - else + if (gmux_read8(gmux_data, GMUX_PORT_SWITCH_DISPLAY) & 1) gmux_data->switch_state_display = VGA_SWITCHEROO_DIS; + else + gmux_data->switch_state_display = VGA_SWITCHEROO_IGD; if (gmux_read8(gmux_data, GMUX_PORT_SWITCH_EXTERNAL) == 2) gmux_data->switch_state_external = VGA_SWITCHEROO_IGD; -- 2.39.1
