Greetings, while testing a snapshot from the last CVS tree with a freshly installed amd64 FreeBSD 6.2 guest I noticed the following errors at boot time :
ad0: 2048MB <QEMU HARDDISK 0.8.3> at ata0-master WDMA2 ad0: FAILURE - READ_DMA timed out LBA=4194301 acd0: CDROM <QEMU CD-ROM/0.8.3> at ata1-master WDMA2 acd0: TIMEOUT - READ BIG retrying (1 retry left) after the system finishes booting there are apparently no more timeouts and the disk reports it is using UDMA2 through atacontrol but the IO performance is poor while reads to the virtual disk around the same sector (the disk is 4194304 sectors long) that failed work fine. # atacontrol mode ad0 current mode = WDMA2 # atacontrol cap ad0 Protocol ATA/ATAPI revision 7 device model QEMU HARDDISK serial number QM00001 firmware revision 0.8.3 cylinders 4161 heads 16 sectors/track 63 lba supported 4194304 sectors lba48 supported 4194304 sectors dma supported overlap not supported the same can be reproduced with a FreeBSD 6.1 guest and also with i386 guests including an old FreeBSD 5.3 guest and even with an amd64 Debian GNU/kFreeBSD guest but AFAIK not with Linux, OpenBSD or [Open]Solaris. the following are the details as detected by the FreeBSD kernel at boot from dmesg (the relevant stuff) : acpi0: <QEMU QEMURSDT> on motherboard pcib0: <ACPI Host-PCI bridge> port 0xcf8-0xcff on acpi0 pci0: <ACPI PCI bus> on pcib0 atapci0: <Intel PIIX3 WDMA2 controller> port 0x1f0-0x1f7,0x3f6,0x170-0x177,0x376,0xc000-0xc00f at device 1.1 on pci0 ata0: <ATA channel 0> on atapci0 ata1: <ATA channel 1> on atapci0 the ata driver is configured to ask the devide for the available modes and seems to be getting DMA2 and PIO4 from it, while defaulting to DMA as configured. the problem goes away if it is forced to run in PIO4 mode which is the only possibility for the FreeBSD 5.3 system which otherwise hungs at boot. the problem doesn't exist in qemu 0.8.2 and is therefore a regression, but i'd yet to bisect the last changes to find the culprit, and since it seems to be a FreeBSD only problem I am first adding debugging to the guest kernel, to track it from the guest side. nonetheless wanted to send this email, so that you guys had a heads up, and to see if anyone had any ideas or some similar problems in other platforms (I am using a Gentoo Linux Host). Carlo _______________________________________________ Qemu-devel mailing list Qemu-devel@nongnu.org http://lists.nongnu.org/mailman/listinfo/qemu-devel
