flashrom: Provide some hints for the user in case /dev/mem mmap fails.

resolves #121

Signed-off-by: Peter Stuge <peter@stuge.se>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@3889 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1

diff --git a/util/flashrom/flashrom.c b/util/flashrom/flashrom.c
index f613f8a0712ee2377e4a512af2bd74761f5c2a7c..7e52fbc8dc6b9d4072588fec6fed9d73249a432b 100644 (file)
--- a/util/flashrom/flashrom.c
+++ b/util/flashrom/flashrom.c
@@ -139,6 +139,13 @@ struct flashchip *probe_flash(struct flashchip *first_flash, int force)
                            fd_mem, (off_t) base);
                if (bios == MAP_FAILED) {
                        perror("Can't mmap memory using " MEM_DEV);
+                       if (EINVAL == errno) {
+                               fprintf(stderr, "In Linux this error can be caused by the CONFIG_NONPROMISC_DEVMEM (<2.6.27),\n");
+                               fprintf(stderr, "CONFIG_STRICT_DEVMEM (>=2.6.27) and CONFIG_X86_PAT kernel options.\n");
+                               fprintf(stderr, "Please check if either is enabled in your kernel before reporting a failure.\n");
+                               fprintf(stderr, "You can override CONFIG_X86_PAT at boot with the nopat kernel parameter but\n");
+                               fprintf(stderr, "disabling the other option unfortunately requires a kernel recompile. Sorry!\n");
+                       }
                        exit(1);
                }
                flash->virtual_memory = bios;