On Fri, Nov 20, 2009 at 01:03:51PM -0500, Kevin O'Connor wrote:
> I've looked into this, and it looks like the cdrom is left in an odd
> state. At this point, I think SeaBIOS is tickling a bug outside of
> seabios (eg, in Vista or qemu). I would appreciate it someone with
> cdrom knowledge of qemu could help.
[...]
> SeaBIOS has a different ata drive detection mechanism than bochs - it
> needs it in order to work on real hardware. So, this explains why
> bochs bios doesn't show this issue. (Seabios tries to send an
> "identify packet device" and then an "identify device" command to
> detect a drive; bochs bios looks for a signature in the ata registers
> after an ata reset.)
It looks like I spoke too soon. It appears the SeaBIOS init can leave
the ATA controller in an interrupts disabled state. This appears to
confuse Vista. So, this is a SeaBIOS bug - I'll implement a fix.
The patch below enables Vista to see the cdrom (though, it's not a
real fix).
-Kevin
--- a/src/ata.c
+++ b/src/ata.c
@@ -237,6 +237,7 @@ send_cmd(struct drive_s *drive_g, struct ata_pio_command *cmd)
return -4;
}
if (!(status & ATA_CB_STAT_DRQ)) {
+ outb(ATA_CB_DC_HD15, iobase2+ATA_CB_DC);
dprintf(6, "send_cmd : DRQ not set (status %02x)\n", status);
return -5;
}
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