diff --git a/xf86drm.c b/xf86drm.c
index 52add5e4..9b97bbb6 100644
--- a/xf86drm.c
+++ b/xf86drm.c
@@ -2864,7 +2864,7 @@ static int drmParsePciBusInfo(int maj, int min, drmPciBusInfoPtr info)
 {
 #ifdef __linux__
     char path[PATH_MAX + 1];
-    char data[128 + 1];
+    char data[512 + 1];
     char *str;
     int domain, bus, dev, func;
     int fd, ret;
@@ -2875,7 +2875,7 @@ static int drmParsePciBusInfo(int maj, int min, drmPciBusInfoPtr info)
         return -errno;
 
     ret = read(fd, data, sizeof(data));
-    data[128] = '\0';
+    data[sizeof(data)-1] = '\0';
     close(fd);
     if (ret < 0)
         return -errno;