Restore __HAVE_KERNEL_CTX_SWITCH, required for the sparc drm module in the

    kernel tree. Added comments to that effect.

diff --git a/linux-core/drm_drv.c b/linux-core/drm_drv.c
index 30a6b6e..016f919 100644 (file)
--- a/linux-core/drm_drv.c
+++ b/linux-core/drm_drv.c
@@ -88,6 +88,13 @@
 #ifndef __HAVE_SG
 #define __HAVE_SG                      0
 #endif
+/* __HAVE_KERNEL_CTX_SWITCH isn't used by any of the drm modules in
+ * the DRI cvs tree, but it is required by the kernel tree's sparc
+ * driver.
+ */
+#ifndef __HAVE_KERNEL_CTX_SWITCH
+#define __HAVE_KERNEL_CTX_SWITCH       0
+#endif
 #ifndef __HAVE_DRIVER_FOPS_READ
 #define __HAVE_DRIVER_FOPS_READ                0
 #endif
@@ -1105,6 +1112,16 @@ int DRM(lock)( struct inode *inode, struct file *filp,
                        DRIVER_DMA_QUIESCENT();
                }
 #endif
+               /* __HAVE_KERNEL_CTX_SWITCH isn't used by any of the
+                * drm modules in the DRI cvs tree, but it is required
+                * by the Sparc driver.
+                */
+#if __HAVE_KERNEL_CTX_SWITCH
+               if ( dev->last_context != lock.context ) {
+                       DRM(context_switch)(dev, dev->last_context,
+                                           lock.context);
+               }
+#endif
         }
 
         DRM_DEBUG( "%d %s\n", lock.context, ret ? "interrupted" : "has lock" );
@@ -1141,6 +1158,29 @@ int DRM(unlock)( struct inode *inode, struct file *filp,
 
        atomic_inc( &dev->counts[_DRM_STAT_UNLOCKS] );
 
+       /* __HAVE_KERNEL_CTX_SWITCH isn't used by any of the drm
+        * modules in the DRI cvs tree, but it is required by the
+        * Sparc driver.
+        */
+#if __HAVE_KERNEL_CTX_SWITCH
+       /* We no longer really hold it, but if we are the next
+        * agent to request it then we should just be able to
+        * take it immediately and not eat the ioctl.
+        */
+       dev->lock.filp = 0;
+       {
+               __volatile__ unsigned int *plock = &dev->lock.hw_lock->lock;
+               unsigned int old, new, prev, ctx;
+
+               ctx = lock.context;
+               do {
+                       old  = *plock;
+                       new  = ctx;
+                       prev = cmpxchg(plock, old, new);
+               } while (prev != old);
+       }
+       wake_up_interruptible(&dev->lock.lock_queue);
+#else
        DRM(lock_transfer)( dev, &dev->lock.hw_lock->lock,
                            DRM_KERNEL_CONTEXT );
 #if __HAVE_DMA_SCHEDULE
@@ -1149,8 +1189,9 @@ int DRM(unlock)( struct inode *inode, struct file *filp,
 
        if ( DRM(lock_free)( dev, &dev->lock.hw_lock->lock,
                             DRM_KERNEL_CONTEXT ) ) {
-          DRM_ERROR( "\n" );
+               DRM_ERROR( "\n" );
        }
+#endif /* !__HAVE_KERNEL_CTX_SWITCH */
 
        unblock_all_signals();
        return 0;

diff --git a/linux/drm_drv.h b/linux/drm_drv.h
index 30a6b6e..016f919 100644 (file)
--- a/linux/drm_drv.h
+++ b/linux/drm_drv.h
@@ -88,6 +88,13 @@
 #ifndef __HAVE_SG
 #define __HAVE_SG                      0
 #endif
+/* __HAVE_KERNEL_CTX_SWITCH isn't used by any of the drm modules in
+ * the DRI cvs tree, but it is required by the kernel tree's sparc
+ * driver.
+ */
+#ifndef __HAVE_KERNEL_CTX_SWITCH
+#define __HAVE_KERNEL_CTX_SWITCH       0
+#endif
 #ifndef __HAVE_DRIVER_FOPS_READ
 #define __HAVE_DRIVER_FOPS_READ                0
 #endif
@@ -1105,6 +1112,16 @@ int DRM(lock)( struct inode *inode, struct file *filp,
                        DRIVER_DMA_QUIESCENT();
                }
 #endif
+               /* __HAVE_KERNEL_CTX_SWITCH isn't used by any of the
+                * drm modules in the DRI cvs tree, but it is required
+                * by the Sparc driver.
+                */
+#if __HAVE_KERNEL_CTX_SWITCH
+               if ( dev->last_context != lock.context ) {
+                       DRM(context_switch)(dev, dev->last_context,
+                                           lock.context);
+               }
+#endif
         }
 
         DRM_DEBUG( "%d %s\n", lock.context, ret ? "interrupted" : "has lock" );
@@ -1141,6 +1158,29 @@ int DRM(unlock)( struct inode *inode, struct file *filp,
 
        atomic_inc( &dev->counts[_DRM_STAT_UNLOCKS] );
 
+       /* __HAVE_KERNEL_CTX_SWITCH isn't used by any of the drm
+        * modules in the DRI cvs tree, but it is required by the
+        * Sparc driver.
+        */
+#if __HAVE_KERNEL_CTX_SWITCH
+       /* We no longer really hold it, but if we are the next
+        * agent to request it then we should just be able to
+        * take it immediately and not eat the ioctl.
+        */
+       dev->lock.filp = 0;
+       {
+               __volatile__ unsigned int *plock = &dev->lock.hw_lock->lock;
+               unsigned int old, new, prev, ctx;
+
+               ctx = lock.context;
+               do {
+                       old  = *plock;
+                       new  = ctx;
+                       prev = cmpxchg(plock, old, new);
+               } while (prev != old);
+       }
+       wake_up_interruptible(&dev->lock.lock_queue);
+#else
        DRM(lock_transfer)( dev, &dev->lock.hw_lock->lock,
                            DRM_KERNEL_CONTEXT );
 #if __HAVE_DMA_SCHEDULE
@@ -1149,8 +1189,9 @@ int DRM(unlock)( struct inode *inode, struct file *filp,
 
        if ( DRM(lock_free)( dev, &dev->lock.hw_lock->lock,
                             DRM_KERNEL_CONTEXT ) ) {
-          DRM_ERROR( "\n" );
+               DRM_ERROR( "\n" );
        }
+#endif /* !__HAVE_KERNEL_CTX_SWITCH */
 
        unblock_all_signals();
        return 0;