If the handler registers late, already registered clients must reprobe their connectors in case they require the handler to switch DDC lines. That is the case on MacBook Pros, which use a gmux chip as handler.
Inspired by Matthew Garrett, who did this in vga_switcheroo_enable() instead, which delayed reprobing until a second gpu registers. Probably makes sense to do this as early as possible, particularly since a second gpu may never register if its driver is blacklisted or not installed: http://lists.freedesktop.org/archives/dri-devel/2014-June/060941.html Signed-off-by: Lukas Wunner <lukas at wunner.de> --- drivers/gpu/vga/vga_switcheroo.c | 8 ++++++++ include/linux/vga_switcheroo.h | 1 + 2 files changed, 9 insertions(+) diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c index 062fafe..3b13e9a 100644 --- a/drivers/gpu/vga/vga_switcheroo.c +++ b/drivers/gpu/vga/vga_switcheroo.c @@ -108,6 +108,8 @@ static void vga_switcheroo_enable(void) int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler) { + struct vga_switcheroo_client *client; + mutex_lock(&vgasr_mutex); if (vgasr_priv.handler) { mutex_unlock(&vgasr_mutex); @@ -115,6 +117,12 @@ int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler) } vgasr_priv.handler = handler; + + /* clients which registered before the handler must reprobe */ + list_for_each_entry(client, &vgasr_priv.clients, list) + if (!client->active && client->ops->reprobe_connectors) + client->ops->reprobe_connectors(client->pdev); + if (vga_switcheroo_ready()) { printk(KERN_INFO "vga_switcheroo: enabled\n"); vga_switcheroo_enable(); diff --git a/include/linux/vga_switcheroo.h b/include/linux/vga_switcheroo.h index 60c9d65..c3ad8bf 100644 --- a/include/linux/vga_switcheroo.h +++ b/include/linux/vga_switcheroo.h @@ -40,6 +40,7 @@ struct vga_switcheroo_handler { struct vga_switcheroo_client_ops { void (*set_gpu_state)(struct pci_dev *dev, enum vga_switcheroo_state); void (*reprobe)(struct pci_dev *dev); + void (*reprobe_connectors)(struct pci_dev *dev); bool (*can_switch)(struct pci_dev *dev); }; -- 1.8.5.2 (Apple Git-48)
