Stefan Hajnoczi <stefa...@gmail.com> writes: > Several of us have been investigating CD-ROM bugs. Let's update each > other, make sure we're not duplicating effort, and see if we can help > each other make progress. > > = Stefan = > > Guests do not notice media change when using Linux host CD-ROM > pass-through for two reasons: > 1. QEMU is caching the device size for removable media and never updating it. > 2. On Linux hosts the /dev/cdrom file descriptor needs to be reopened > to refresh the underlying device size. > > Patches have been posted to qemu-devel. > > Libvirt does not recognize eject failure due to locked tray. This > causes libvirt to get out-of-sync and believe the medium was > successfully changed. A libvirt fix is in progress: > https://bugzilla.redhat.com/show_bug.cgi?id=689101 > > = Anthony = > > Using 'change' or scripted commands without a delay between closing > the BlockDriverState and opening the new CD-ROM. The guest does not > have a chance to poll the drive and determine a medium present -> > medium not present transition followed by a medium not present -> > medium present transition. > > A fix for this does not exist yet and might be tricky since we need to > delay or wait for the guest to poll once before opening the new > CD-ROM. > > = Amit = > > Found that 2.6.38 and later guest kernels fail to report media change. > The new in-kernel media change polling framework issues ATAPI > commands which are not implemented in hw/ide/core.c. > > = Juan = > > ATA HSM violation errors after live migration while CD-ROM read > operations. This is probably a hw/ide/* or DMA migration bug.
Note Amit's bug also triggers ATA HSM errors. Might be related. > = Markus = > > ? I've wrestled with a few issues: * udev choked on unimplemented GPCMD_READ_DISC_INFO. udev maintainer fixed the bad error recovery. * Lika Amit and Juan, I ran into the ATA HSM errors after media change. * anaconda sometimes fails to recognize an install disk after the media check or a media change. Could be related to media change bugs / unimplemented commands. * Need to wrap this up: Subject: [RFC PATCH] block: Fix eject -f for locked devices Date: Fri, 18 Feb 2011 16:16:07 +0100 Message-ID: <m3oc69jruw....@blackfin.pond.sub.org> A common theme seems to be the incomplete emulation. I figure we should make an effort to implement the mandatory parts of the relevant specs. Guest software can't be expected to handle missing mandatory features gracefully.
