On 04.09.2012, at 16:08, Jason Baron wrote: > While testing q35, I found that windows 7 (specifically, windows 7 ultimate > with sp1 x64), wouldn't install because it can't find the cdrom or disk drive. > The failure message is: 'A required cd/dvd device driver is missing. If you > have a driver floppy disk, CD, DVD, or USB flash drive, please insert it now.' > This can also be reproduced on piix by adding an ahci controller, and > observing that windows 7 does not see any devices behind it. > > The problem is that when windows issues a HBA reset, qemu does not reset the > individual ports' PxCMD register. Windows 7 then reads back the PxCMD register > and presumably assumes that the ahci controller has already been initialized. > Windows then never sets up the PxIE register to enable interrupts, and thus it > never gets irqs back when it sends ata device inquiry commands. > > This change brings qemu into ahci 1.3 specification compliance. > > Section 10.4.3 HBA Reset: > > " > When GHC.HR is set to '1', GHC.AE, GHC.IE, the IS register, and all port > register fields (except PxFB/PxFBU/PxCLB/PxCLBU) that are not HwInit in the > HBA's register memory space are reset. > " > > I've also re-tested Fedora 16 and 17 to verify that they continue to work with > this change. > > Signed-off-by: Jason Baron <jba...@redhat.com>
Awesome, a lot cleaner now :). Acked-by: Alexander Graf <ag...@suse.de>
