Deferring initiailzation of the secondary GPU until switcheroo is ready
will allow successfully reading the EDID in systems which support muxing
the DDC seperately from the display.

Signed-off-by: Seth Forshee <seth.forshee at canonical.com>
---
 drivers/gpu/drm/drm_drv.c |    3 +
 drivers/gpu/drm/drm_pci.c |  141 +++++++++++++++++++++++++++++++++++++++------
 include/drm/drmP.h        |    2 +
 3 files changed, 129 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 9238de4..124fd8a 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -276,6 +276,8 @@ static int __init drm_core_init(void)
                goto err_p3;
        }

+       drm_pci_module_init();
+
        DRM_INFO("Initialized %s %d.%d.%d %s\n",
                 CORE_NAME, CORE_MAJOR, CORE_MINOR, CORE_PATCHLEVEL, CORE_DATE);
        return 0;
@@ -291,6 +293,7 @@ err_p1:

 static void __exit drm_core_exit(void)
 {
+       drm_pci_module_exit();
        remove_proc_entry("dri", NULL);
        debugfs_remove(drm_debugfs_root);
        drm_sysfs_destroy();
diff --git a/drivers/gpu/drm/drm_pci.c b/drivers/gpu/drm/drm_pci.c
index 4896c96..9da0cd2 100644
--- a/drivers/gpu/drm/drm_pci.c
+++ b/drivers/gpu/drm/drm_pci.c
@@ -40,6 +40,9 @@
 #include <linux/slab.h>
 #include <linux/dma-mapping.h>
 #include <linux/export.h>
+#include <linux/notifier.h>
+#include <linux/vgaarb.h>
+#include <linux/vga_switcheroo.h>
 #include "drmP.h"

 /**********************************************************************/
@@ -297,19 +300,8 @@ static struct drm_bus drm_pci_bus = {
        .agp_init = drm_pci_agp_init,
 };

-/**
- * Register.
- *
- * \param pdev - PCI device structure
- * \param ent entry from the PCI ID table with device type flags
- * \return zero on success or a negative number on failure.
- *
- * Attempt to gets inter module "drm" information. If we are first
- * then register the character device and inter module information.
- * Try and register, if we fail to register, backout previous work.
- */
-int drm_get_pci_dev(struct pci_dev *pdev, const struct pci_device_id *ent,
-                   struct drm_driver *driver)
+int __drm_get_pci_dev(struct pci_dev *pdev, const struct pci_device_id *ent,
+                     struct drm_driver *driver)
 {
        struct drm_device *dev;
        int ret;
@@ -334,8 +326,6 @@ int drm_get_pci_dev(struct pci_dev *pdev, const struct 
pci_device_id *ent,
        dev->hose = pdev->sysdata;
 #endif

-       mutex_lock(&drm_global_mutex);
-
        if ((ret = drm_fill_in_dev(dev, ent, driver))) {
                printk(KERN_ERR "DRM: Fill_in_dev failed.\n");
                goto err_g2;
@@ -371,7 +361,6 @@ int drm_get_pci_dev(struct pci_dev *pdev, const struct 
pci_device_id *ent,
                 driver->name, driver->major, driver->minor, driver->patchlevel,
                 driver->date, pci_name(pdev), dev->primary->index);

-       mutex_unlock(&drm_global_mutex);
        return 0;

 err_g4:
@@ -386,10 +375,116 @@ err_g1:
        mutex_unlock(&drm_global_mutex);
        return ret;
 }
+
+struct deferred_init_data {
+       struct list_head list;
+       struct pci_dev *pdev;
+       const struct pci_device_id *ent;
+       struct drm_driver *driver;
+};
+
+static LIST_HEAD(deferred_init_list);
+
+static void drm_deferred_init_work_fn(struct work_struct *work)
+{
+       struct deferred_init_data *di_data, *temp;
+
+       mutex_lock(&drm_global_mutex);
+
+       if (!vga_switcheroo_handler_registered() ||
+           !vga_switcheroo_get_active_client()) {
+               mutex_unlock(&drm_global_mutex);
+               return;
+       }
+
+       list_for_each_entry_safe(di_data, temp, &deferred_init_list, list) {
+               if (__drm_get_pci_dev(di_data->pdev, di_data->ent,
+                                     di_data->driver))
+                       DRM_ERROR("pci device initialization failed\n");
+               list_del(&di_data->list);
+               kfree(di_data);
+       }
+       mutex_unlock(&drm_global_mutex);
+}
+static DECLARE_WORK(deferred_init_work, drm_deferred_init_work_fn);
+
+static int drm_switcheroo_notifier_fn(struct notifier_block *nb,
+                                     unsigned long val, void *unused)
+{
+       if (val == VGA_SWITCHEROO_CLIENT_REGISTERED ||
+           val == VGA_SWITCHEROO_HANDLER_REGISTERED)
+               queue_work(system_nrt_wq, &deferred_init_work);
+       return NOTIFY_OK;
+}
+static struct notifier_block drm_switcheroo_notifier = {
+       .notifier_call = drm_switcheroo_notifier_fn,
+};
+
+/**
+ * Register.
+ *
+ * \param pdev - PCI device structure
+ * \param ent entry from the PCI ID table with device type flags
+ * \return zero on success or a negative number on failure.
+ *
+ * Attempt to gets inter module "drm" information. If we are first
+ * then register the character device and inter module information.
+ * Try and register, if we fail to register, backout previous work.
+ */
+int drm_get_pci_dev(struct pci_dev *pdev, const struct pci_device_id *ent,
+                   struct drm_driver *driver)
+{
+       int ret = 0;
+
+       mutex_lock(&drm_global_mutex);
+
+       /*
+        * For secondary graphics devices shouldn't be initialized
+        * until the handler and primary graphics device have been
+        * registered with vga_switcheroo.
+        *
+        * FIXME: Is vga_default_device() reliable enough for this
+        * purpose?
+        *
+        * FIXME: If vga_switcheroo is disabled secondary devices
+        * never gets initialized. Is this okay? Maybe it is, since
+        * we can't switch to the secondary GPU anyway.
+        */
+       if (vga_default_device() == pdev ||
+           (vga_switcheroo_handler_registered() &&
+            vga_switcheroo_get_active_client())) {
+               ret = __drm_get_pci_dev(pdev, ent, driver);
+       } else {
+               struct deferred_init_data *di_data =
+                       kmalloc(sizeof(*di_data), GFP_KERNEL);
+               if (!di_data) {
+                       ret = -ENOMEM;
+               } else {
+                       di_data->pdev = pdev;
+                       di_data->ent = ent;
+                       di_data->driver = driver;
+                       list_add_tail(&di_data->list, &deferred_init_list);
+               }
+       }
+
+       return ret;
+}
 EXPORT_SYMBOL(drm_get_pci_dev);

 void drm_put_pci_dev(struct drm_device *dev)
 {
+       struct deferred_init_data *di_data;
+
+       mutex_lock(&drm_global_mutex);
+       list_for_each_entry(di_data, &deferred_init_list, list) {
+               if (di_data->pdev == dev->pdev) {
+                       list_del(&di_data->list);
+                       kfree(di_data);
+                       break;
+               }
+       }
+       mutex_unlock(&drm_global_mutex);
+
        drm_put_dev(dev);
 }
 EXPORT_SYMBOL(drm_put_pci_dev);
@@ -466,7 +561,7 @@ void drm_pci_exit(struct drm_driver *driver, struct 
pci_driver *pdriver)
                pci_unregister_driver(pdriver);
        } else {
                list_for_each_entry_safe(dev, tmp, &driver->device_list, 
driver_item)
-                       drm_put_dev(dev);
+                       drm_put_pci_dev(dev);
        }
        DRM_INFO("Module unloaded\n");
 }
@@ -520,3 +615,15 @@ int drm_pcie_get_speed_cap_mask(struct drm_device *dev, 
u32 *mask)
        return 0;
 }
 EXPORT_SYMBOL(drm_pcie_get_speed_cap_mask);
+
+int drm_pci_module_init(void)
+{
+       return vga_switcheroo_register_notifier(&drm_switcheroo_notifier);
+}
+EXPORT_SYMBOL(drm_pci_module_init);
+
+void drm_pci_module_exit(void)
+{
+       vga_switcheroo_unregister_notifier(&drm_switcheroo_notifier);
+}
+EXPORT_SYMBOL(drm_pci_module_exit);
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index eb99e96..0e9401f 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1749,6 +1749,8 @@ extern int drm_get_pci_dev(struct pci_dev *pdev,
                           const struct pci_device_id *ent,
                           struct drm_driver *driver);
 extern void drm_put_pci_dev(struct drm_device *dev);
+extern int drm_pci_module_init(void);
+extern void drm_pci_module_exit(void);

 #define DRM_PCIE_SPEED_25 1
 #define DRM_PCIE_SPEED_50 2
-- 
1.7.9.5

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