File qemu-cvs-alsa_mmap.patch of Package qemu

File qemu-cvs-alsa_mmap.patch of Package qemu (Revision 962faeafa4221564c4bc465af39443ad)

Currently displaying revision 962faeafa4221564c4bc465af39443ad, show latest

Index: qemu/linux-user/mmap.c
================================================================================
--- qemu/linux-user/mmap.c
+++ qemu/linux-user/mmap.c
@@ -153,6 +153,9 @@
     return 0;
 }
 
+#define SNDRV_PCM_MMAP_OFFSET_STATUS  0x80000000
+#define SNDRV_PCM_MMAP_OFFSET_CONTROL 0x81000000
+
 /* NOTE: all the constants are the HOST ones */
 abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
                      int flags, int fd, abi_ulong offset)
@@ -194,6 +197,17 @@
     }
 #endif
 
+    /* Alsa tries to communcate with the kernel via mmap. This usually
+     * is a good idea when user- and kernelspace are running on the 
+     * same architecture but does not work out when not. To make alsa
+     * not to use mmap, we can just have it fail on the mmap calls that
+     * would initiate this.
+     */
+    if(offset == SNDRV_PCM_MMAP_OFFSET_STATUS || offset == SNDRV_PCM_MMAP_OFFSET_CONTROL) {
+	errno = EINVAL;
+	return -1;
+    }
+
     if (offset & ~TARGET_PAGE_MASK) {
         errno = EINVAL;
         return -1;