[SeaBIOS] Seabios unable to boot Fedora-based instances

[Kevin O'Connor]

On Thu, Aug 10, 2017 at 11:18:32AM +0200, Maciej Józefczyk wrote:
> Hello,
> 
> Environment: Seabios master dd9bba5b9c1d5175a2757f3fdc9d554b4c8eea3a
> Qemu: 1:2.5+dfsg-5ubuntu10.14
> OS: Ubuntu 16.04
> 
> We found that newest Seabios (dd9bba5b9c1d5175a2757f3fdc9d554b4c8eea3a)
> is not working with latest Fedora 26 - image taken from:
> https://download.fedoraproject.org/pub/fedora/linux/releases/26/CloudImages/x86_64/images/Fedora-Cloud-Base-26-1.5.x86_64.qcow2
> 
> Each time it hangs on "Probing EDD (edd=off to disable)... OK".
> 
> We discovered that rollback to version 4902b8a7 solves the problem. It
> seems that something is wrong with 4902b8a7. After fetch lastest master
> and rollback of 4902b8a7 - Fedora is able to boot.
> 
> Ubuntu is booting all the time without problem.
> 
> Could you take a look on this?

Thanks.  I do see a defect in 4902b8a7 - it is not generating linesize
correctly (see patch below).

-Kevin


--- a/vgasrc/stdvga.c
+++ b/vgasrc/stdvga.c
@@ -324,7 +324,7 @@ stdvga_set_dacformat(struct vgamode_s *vmode_g, int val)
 int
 stdvga_get_linesize(struct vgamode_s *vmode_g)
 {
-    return DIV_ROUND_UP(vmode_g->width * vga_bpp(vmode_g), 8);
+    return DIV_ROUND_UP(GET_GLOBAL(vmode_g->width) * vga_bpp(vmode_g), 8);
 }
 
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