[Qemu-devel] [RFC 01/10] fdc: Make default FDrive type explicit

[John Snow <jsnow@redhat.com>]

What happens currently is if a drive is not inserted, we
won't match any of the drive types (None) or the geometries,
so we'll wind up picking the very first drive (1.44MB type)
as a default.

This patch makes the default picking a lot more explicit.

If a floppy image is inserted, QEMU will continue as it has
in the past to choose the drive type based on the image provided.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 hw/block/fdc.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/hw/block/fdc.c b/hw/block/fdc.c
index 5e1b67e..cdf9e09 100644
--- a/hw/block/fdc.c
+++ b/hw/block/fdc.c
@@ -123,6 +123,13 @@ static void pick_geometry(BlockBackend *blk, int *nb_heads,
     uint64_t nb_sectors, size;
     int i, first_match, match;
 
+    /* Pick a default drive type if there's no media inserted AND we have
+     * not yet announced our drive type to the CMOS. */
+    if (!blk_is_inserted(blk) && drive_in == FDRIVE_DRV_NONE) {
+        parse = &fd_formats[0];
+        goto out;
+    }
+
     blk_get_geometry(blk, &nb_sectors);
     match = -1;
     first_match = -1;
@@ -152,6 +159,8 @@ static void pick_geometry(BlockBackend *blk, int *nb_heads,
         }
         parse = &fd_formats[match];
     }
+
+ out:
     *nb_heads = parse->max_head + 1;
     *max_track = parse->max_track;
     *last_sect = parse->last_sect;
-- 
2.1.0