omap24xx: Add workaround for omapfb locking bug.

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@29201 3c298f89-4303-0410-b956-a3cf2f4a3e73

diff --git a/target/linux/omap24xx/patches-3.1/309-omapfb-circular-mutex-workaround.patch b/target/linux/omap24xx/patches-3.1/309-omapfb-circular-mutex-workaround.patch
new file mode 100644 (file)
index 0000000..161698d
--- /dev/null
+++ b/target/linux/omap24xx/patches-3.1/309-omapfb-circular-mutex-workaround.patch
@@ -0,0 +1,45 @@
+Index: linux-3.1.1/drivers/video/omap/omapfb_main.c
+===================================================================
+--- linux-3.1.1.orig/drivers/video/omap/omapfb_main.c  2011-11-11 21:19:27.000000000 +0100
++++ linux-3.1.1/drivers/video/omap/omapfb_main.c       2011-11-16 23:10:16.554325659 +0100
+@@ -419,10 +419,10 @@ static void set_fb_fix(struct fb_info *f
+       fbi->screen_base        = rg->vaddr;
+ 
+       if (!from_init) {
+-              mutex_lock(&fbi->mm_lock);
++              preempt_disable();
+               fix->smem_start         = rg->paddr;
+               fix->smem_len           = rg->size;
+-              mutex_unlock(&fbi->mm_lock);
++              preempt_enable();
+       } else {
+               fix->smem_start         = rg->paddr;
+               fix->smem_len           = rg->size;
+@@ -932,10 +932,10 @@ static int omapfb_setup_mem(struct fb_in
+                                * plane memory is dealloce'd, the other
+                                * screen parameters in var / fix are invalid.
+                                */
+-                              mutex_lock(&fbi->mm_lock);
++                              preempt_disable();
+                               fbi->fix.smem_start = 0;
+                               fbi->fix.smem_len = 0;
+-                              mutex_unlock(&fbi->mm_lock);
++                              preempt_enable();
+                       }
+               }
+       }
+Index: linux-3.1.1/drivers/video/fbmem.c
+===================================================================
+--- linux-3.1.1.orig/drivers/video/fbmem.c     2011-11-11 21:19:27.000000000 +0100
++++ linux-3.1.1/drivers/video/fbmem.c  2011-11-16 23:20:56.055698968 +0100
+@@ -1369,8 +1369,10 @@ fb_mmap(struct file *file, struct vm_are
+       }
+ 
+       /* frame buffer memory */
++      preempt_disable();
+       start = info->fix.smem_start;
+       len = PAGE_ALIGN((start & ~PAGE_MASK) + info->fix.smem_len);
++      preempt_enable();
+       if (off >= len) {
+               /* memory mapped io */
+               off -= len;