[RFC] drm platform multi-device support

[Rob Clark <rob@ti.com>]

From: Rob Clark <robdclark@gmail.com>

Include the minor device id in the bus-id to give userspace a way to open
the correct "cardN" when there are multiple device instances.
---
It may seem a bit strange to have multiple platform device instances, but
we have a use-case for this.  And this relatively simple patch does the
trick.

 drivers/gpu/drm/drm_ioctl.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 47db4df..075024b 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -165,14 +165,15 @@ static int drm_set_busid(struct drm_device *dev, struct drm_file *file_priv)
 		drm_unset_busid(dev, master);
 
 	if (drm_core_check_feature(dev, DRIVER_USE_PLATFORM_DEVICE)) {
-		master->unique_len = 10 + strlen(dev->platformdev->name);
+		master->unique_len = 13 + strlen(dev->platformdev->name);
+		master->unique_size = master->unique_len;
 		master->unique = kmalloc(master->unique_len + 1, GFP_KERNEL);
 
 		if (master->unique == NULL)
 			return -ENOMEM;
 
 		len = snprintf(master->unique, master->unique_len,
-			"platform:%s", dev->platformdev->name);
+			"platform:%s:%02d", dev->platformdev->name, dev->primary->index);
 
 		if (len > master->unique_len) {
 			DRM_ERROR("Unique buffer overflowed\n");
-- 
1.7.1