[Qemu-ppc] BUG: qemu-system-ppc boots Mac OS 9.2.1/9.2.2 iso's extremely slow

[Howard Spoelstra]

Hi,

I noticed qemu-system-ppc currently has difficulty booting Mac OS
9.2.1/9.2.2 iso's. Even after 5 minutes the happy mac hasn't appeared.
This does not happen with 9.0.4 or 9.1 iso's, or PPC OS X versions.

I bisected to this commit:

95ed56939eb2eaa4e2f349fe6dcd13ca4edfd8fb is the first bad commit
commit 95ed56939eb2eaa4e2f349fe6dcd13ca4edfd8fb
Author: Li Qiang <address@hidden>
Date:   Tue Feb 7 02:23:33 2017 -0800

    usb: ohci: limit the number of link eds

    The guest may builds an infinite loop with link eds. This patch
    limit the number of linked ed to avoid this.

    Signed-off-by: Li Qiang <address@hidden>
    Message-id: address@hidden
    Signed-off-by: Gerd Hoffmann <address@hidden>

After reverting boot time is ~20 seconds.

It seems setting "#define ED_LINK_LIMIT 4" in hw/usb/hcd-ohci.c to a
higher limit solves this issue.


Best,
Howard