On Wed, Aug 21, 2019 at 09:31:48AM -0400, Kevin O'Connor wrote: > On Wed, Aug 21, 2019 at 08:42:08AM +0200, Gerd Hoffmann wrote: > > Hi, > > > > > Using the default QEMU config, we build SeaBIOS to use the TSC timer: > > > > > > builds/seabios-128k/.config:CONFIG_TSC_TIMER=y > > > builds/seabios-256k/.config:CONFIG_TSC_TIMER=y > > > > > Do we need a cpu with TSC support to run SeaBIOS? > > > > Hmm. seabios uses pmtimer if available. isapc has no pmtimer though, > > so it uses TSC instead. > > But, SeaBIOS should have automatically detected no TSC and then fallen > back to the PIT. And the check does work correctly with "-cpu 486" in > my tests. > > Is the PIT not working for some reason in the original setup? (Any > time I attempt to run with "-M isapc" I just get an "Unable to unlock > ram - bridge not found" error.)
Yep, that should be no problem, with isapc the ram is not locked in the first place. > The PIT seems to work okay in my > setup. Using the floppy image from https://winworldpc.com/download/49c380c2-a9c3-af25-c389-11c3a6e28094 qemu-system-x86_64 -cpu 486 -M isapc -fda win98se.raw => fails qemu-system-x86_64 -cpu 486,+tsc -M isapc -fda win98se.raw => works cheers, Gerd
