On Fri, 2007-07-13 at 16:46 +0200, Luca wrote: > On 7/13/07, Gregory Haskins <[EMAIL PROTECTED]> wrote:
> Just to clarify: you are suggesting that the "old" IDE driver used to > see that the controller was disabled and reprogrammed it by itself > (fast mode); now it sees it's enabled and leaves whatever mode is > currently set. > I can't look at the sources right now but it's at least plausible ;-) > Yeah. As Im sure you are aware, those bits that your patch modifies are (IIUC) for enabling/disabling access to the legacy IDE. On real hardware, they can be used by the bios to enable/disable the legacy IDE function. It doesnt actually disable the chip IIUC..its just a flag to let higher layer software detect if the legacy IDE is usable. In our emulated environment, those bits were left undefined prior to your patch (neither qemu nor bochs was configuring them). Dont ask me why, but what they initialized to was relatively consistent instead of random. However, you cannot predict which way (on or off) and it seems each environment was somewhat different (e.g. no one else was complaining about the loss of IDE when i first stumbled on it, yet it was consistently broken for me through a couple of releases). So what I am thinking is that the drivers included with the FC7 kernel are defaulting to some kind of slower legacy mode when they see it is available and enabled. Otherwise, they probably load some direct non-legacy PCI driver and use that instead. If this theory pans out, I would suggest we make some kind of flag in qemu "--disable-legacy-ide" where the default is "enabled" (as your patch does today). That way, people with this issue can disable it in the "bios" just like a real system. -Greg ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
