agp: add chipset flushing support to AGP interface

This bumps the AGP interface to 0.103.

Certain Intel chipsets contains a global write buffer, and this can require
flushing from the drm or X.org to make sure all data has hit RAM before
initiating a GPU transfer, due to a lack of coherency with the integrated
graphics device and this buffer.

This just adds generic support to the AGP interfaces, a follow-on patch
will add support to the Intel driver to use this interface.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/char/agp/frontend.c b/drivers/char/agp/frontend.c
index 7791e98de51c..9bd5a958954c 100644
--- a/drivers/char/agp/frontend.c
+++ b/drivers/char/agp/frontend.c
@@ -960,6 +960,13 @@ static int agpioc_unbind_wrap(struct agp_file_private *priv, void __user *arg)
         return agp_unbind_memory(memory);
 }
 
+int agpioc_chipset_flush_wrap(struct agp_file_private *priv)
+{
+        DBG("");
+        agp_flush_chipset(agp_bridge);
+        return 0;
+}
+
 static int agp_ioctl(struct inode *inode, struct file *file,
                      unsigned int cmd, unsigned long arg)
 {
@@ -1033,6 +1040,10 @@ static int agp_ioctl(struct inode *inode, struct file *file,
         case AGPIOC_UNBIND:
                 ret_val = agpioc_unbind_wrap(curr_priv, (void __user *) arg);
                 break;
+               
+        case AGPIOC_CHIPSET_FLUSH:
+                ret_val = agpioc_chipset_flush_wrap(curr_priv);
+                break;
         }
 
 ioctl_out: