Re: [Qemu-devel] [PATCH] Fix media detection on emulated CDROM

[Gary Grebus]

On Tue, 2008-11-18 at 13:18 -0600, Anthony Liguori wrote:
> Gary Grebus wrote:
> > This patch tweaks the ATAPI CDROM emulation to fix an annoyance seen
> > when running a variety of Linux guests: the desktop GUI shows a CDROM
> > device as present, but is unable to automount the media and display its
> > contents.
> >
> > The patch adds the PLAY_AUDIO capability bit to the data returned by
> > MODE_SENSE commands.  That convinces the guest kernel to determine what
> > kind of media is present.
> >
> > Arguably Linux could be smarter about this, but it's my guess there are
> > few (if any) hardware CDROM drives that don't set the bit, and there are
> > a large number of Linux distros that exhibit this problem.
> >
> > Signed-off-by: Gary Grebus <address@hidden>
> >
> >   
> 
> Could you please include a comment to this effect in the code?
> 
> Regards,
> 
> Anthony Liguori

No problem... revised patch below.

-- 
Gary Grebus
Virtual Iron Software, Inc.


Index: hw/ide.c
===================================================================
--- hw/ide.c    (revision 5729)
+++ hw/ide.c    (working copy)
@@ -1603,7 +1603,9 @@
                     buf[10] = 0x00;
                     buf[11] = 0x00;
 
-                    buf[12] = 0x70;
+                    /* Claim PLAY_AUDIO capability (0x01) since some Linux
+                       code checks for this to automount media. */
+                    buf[12] = 0x71;
                     buf[13] = 3 << 5;
                     buf[14] = (1 << 0) | (1 << 3) | (1 << 5);
                     if (bdrv_is_locked(s->bs))