From c1e1655bb892c6800af82c2d88c8063fce7b5c98 Mon Sep 17 00:00:00 2001 From: Matthew Garrett Date: Mon, 16 Nov 2015 21:38:40 +0100 Subject: [PATCH] apple-gmux: Assign apple_gmux_data before registering Registering the handler after both GPUs will trigger a DDC switch for connector reprobing. This will oops if apple_gmux_data hasn't already been assigned. Reorder the code to do that. [Lukas: More generally, this commit fixes a race condition that is triggered by invoking a handler callback between the call to vga_switcheroo_register_handler() and the assignment of apple_gmux_data.] Tested-by: Pierre Moreau [MBP 5,3 2009 nvidia MCP79 + G96 pre-retina 15"] Tested-by: Paul Hordiienko [MBP 6,2 2010 intel ILK + nvidia GT216 pre-retina 15"] Tested-by: Lukas Wunner [MBP 9,1 2012 intel IVB + nvidia GK107 pre-retina 15"] Tested-by: William Brown [MBP 8,2 2011 intel SNB + amd turks pre-retina 15"] Tested-by: Bruno Bierbaumer [MBP 11,3 2013 intel HSW + nvidia GK107 retina 15"] Signed-off-by: Matthew Garrett Reviewed-by: Lukas Wunner Signed-off-by: Lukas Wunner Signed-off-by: Darren Hart --- drivers/platform/x86/apple-gmux.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c index 976efeb3f2ba..aa58d41ec460 100644 --- a/drivers/platform/x86/apple-gmux.c +++ b/drivers/platform/x86/apple-gmux.c @@ -588,18 +588,20 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id) gmux_data->gpe = -1; } + apple_gmux_data = gmux_data; + init_completion(&gmux_data->powerchange_done); + gmux_enable_interrupts(gmux_data); + if (vga_switcheroo_register_handler(&gmux_handler)) { ret = -ENODEV; goto err_register_handler; } - init_completion(&gmux_data->powerchange_done); - apple_gmux_data = gmux_data; - gmux_enable_interrupts(gmux_data); - return 0; err_register_handler: + gmux_disable_interrupts(gmux_data); + apple_gmux_data = NULL; if (gmux_data->gpe >= 0) acpi_disable_gpe(NULL, gmux_data->gpe); err_enable_gpe: