[Qemu-devel] cmdide0:1:0: lost interrupt on NetBSD 7

[Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>]

Whilst testing various images under qemu-system-sparc64, I've noticed a
regression with the new NetBSD 7 release. On boot the kernel hangs just
after detecting the CDROM and eventually outputs "cmdide0:1:0: lost
interrupt" onto the console.

A quick session with git bisect points to the following patch:

9ef2e93f9b1888c7d0deb4a105149138e6ad2e98 is the first bad commit
commit 9ef2e93f9b1888c7d0deb4a105149138e6ad2e98
Author: John Snow <jsnow@redhat.com>
Date:   Thu Sep 17 14:17:05 2015 -0400

    atapi: abort transfers with 0 byte limits

    We're supposed to abort on transfers like this, unless we fill
    Word 125 of our IDENTIFY data with a default transfer size, which
    we don't currently do.

    This is an ATA error, not a SCSI/ATAPI one.
    See ATA8-ACS3 sections 7.17.6.49 or 7.21.5.

    If we don't do this, QEMU will loop forever trying to transfer
    zero bytes, which isn't particularly useful.

    Signed-off-by: John Snow <jsnow@redhat.com>
    Reviewed-by: Markus Armbruster <armbru@redhat.com>
    Message-id: 1442253685-23349-2-git-send-email-jsnow@redhat.com

Reproducing the bug is easy enough using the command line below:

./qemu-system-sparc64 -cdrom NetBSD-7.0-sparc64.iso -boot d -nographic

Testing also shows that NetBSD 6 is apparently unaffected by this change.


ATB,

Mark.