On Fri, Sep 30, 2011 at 9:14 AM, Peter Maydell <peter.mayd...@linaro.org> wrote: > On 30 September 2011 07:47, Jan Kiszka <jan.kis...@web.de> wrote: >> There is no difference between system reset after power-up or later on. >> And there should be no difference between per device, per group of >> devices or system-wide reset. A device model cannot tell these apart. > > I think it's also useful to distinguish "system reset" meaning 'simulated > reset button was pressed, causing the reset line to be asserted on various > devices' from "simulation reset" meaning 'qemu effectively tore down the > whole simulation and put it into the same state it would be when qemu > initially starts'. I don't think you can usefully reset a single device > except by asserting its simulated reset signal, except possibly for > hotplug type situations where you're simulating applying power to it.
In the 2009 thread, i286 triple fault was mentioned. It's also possible to reset a single device, which can then reset a slave device and so forth, like Sparc32 DMA controller can reset ESP device and that should perform a SCSI bus reset. >> My series does not depend on this cleanup/fix, but the reason not to >> apply remains wrong IMHO. > > (just to be clear) I'm not arguing against your patch, just more > generally that I'm not sure our current model of reset is entirely > coherent. > > -- PMM >