On Fri, Aug 24, 2012 at 06:39:02AM +0200, Alexander Graf 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. > > > > I believe 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. > > What a nasty little bug. If it makes it work for you, the change is all fine > from my POV (and should go into 1.2). >
Ok, I don't see it 1.2.0-rc2. If others are ok with this for 1.2, whose tree should this go through? Thanks, -Jason
