Originally by Seth Forshee <seth.forshee@xxxxxxxxxxxxx>, 2012-10-04: The gmux allows muxing the DDC independently from the display, so support this functionality. This will allow reading the EDID for the inactive GPU, fixing issues with machines that either don't have a VBT or have invalid mode data in the VBT. Modified by Lukas Wunner <lukas@xxxxxxxxx>, 2015-03-27: If the inactive client registers before the active client then old_ddc_owner cannot be determined with find_active_client() (null pointer dereference). Therefore change semantics of the ->switch_ddc handler callback to return old_ddc_owner. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=88861 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=61115 Tested-by: Pierre Moreau <pierre.morrow@xxxxxxx> [MBP 5,3 2009 nvidia 9400M + 9600M GT pre-retina] Tested-by: Paul Hordiienko <pvt.gord@xxxxxxxxx> [MBP 6,2 2010 intel ILK + nvidia GT216 pre-retina] Tested-by: William Brown <william@xxxxxxxxxxxxxxxx> [MBP 8,2 2011 intel SNB + amd turks pre-retina] Tested-by: Lukas Wunner <lukas@xxxxxxxxx> [MBP 9,1 2012 intel IVB + nvidia GK107 pre-retina] Tested-by: Bruno Bierbaumer <bruno@xxxxxxxxxxxxxx> [MBP 11,3 2013 intel HSW + nvidia GK107 retina -- work in progress] Cc: Seth Forshee <seth.forshee@xxxxxxxxxxxxx> Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx> --- drivers/platform/x86/apple-gmux.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c index 0dec3f5..08bdf1e 100644 --- a/drivers/platform/x86/apple-gmux.c +++ b/drivers/platform/x86/apple-gmux.c @@ -273,14 +273,34 @@ static const struct backlight_ops gmux_bl_ops = { .update_status = gmux_update_status, }; +static int gmux_switch_ddc(enum vga_switcheroo_client_id id) +{ + enum vga_switcheroo_client_id old_ddc_owner; + + if (gmux_read8(apple_gmux_data, GMUX_PORT_SWITCH_DDC) == 1) + old_ddc_owner = VGA_SWITCHEROO_IGD; + else + old_ddc_owner = VGA_SWITCHEROO_DIS; + + pr_debug("Switching gmux DDC from %d to %d\n", old_ddc_owner, id); + + if (id == old_ddc_owner) + return old_ddc_owner; + + if (id == VGA_SWITCHEROO_IGD) + gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 1); + else + gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 2); + + return old_ddc_owner; +} + static int gmux_switchto(enum vga_switcheroo_client_id id) { if (id == VGA_SWITCHEROO_IGD) { - gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 1); gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DISPLAY, 2); gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 2); } else { - gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 2); gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DISPLAY, 3); gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 3); } @@ -347,6 +367,7 @@ gmux_active_client(struct apple_gmux_data *gmux_data) } static struct vga_switcheroo_handler gmux_handler = { + .switch_ddc = gmux_switch_ddc, .switchto = gmux_switchto, .power_state = gmux_set_power_state, .get_client_id = gmux_get_client_id, -- 2.1.0 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
