On Fri, Dec 9, 2011 at 1:16 PM, Sasha Levin <levinsasha928@xxxxxxxxx> wrote: > The process of probing the 8250 serial port is as follows: > > 1. Start detecting IRQs > 2. Enable the IER register [At this point, the port is supposed to light > the INTR]. > 3. Stop detecting IRQs [At this point, the driver detects which IRQ belongs > to that port]. > 4. Disable IER register. > > Since we weren't enabling and disabling the IRQ based on IER writes, > we would often fail the probing since the driver couldn't detect > which IRQ is used by the port, and would just default that to 0. > > This would cause slowness and may have caused hangs. For me there is a > significant increase in speed of the terminal after this patch. > > Signed-off-by: Sasha Levin <levinsasha928@xxxxxxxxx> > --- > tools/kvm/hw/serial.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/tools/kvm/hw/serial.c b/tools/kvm/hw/serial.c > index 67a2007..8cd47cf 100644 > --- a/tools/kvm/hw/serial.c > +++ b/tools/kvm/hw/serial.c > @@ -233,6 +233,7 @@ static bool serial8250_out(struct ioport *ioport, struct kvm *kvm, u16 port, voi > break; > case UART_IER: > dev->ier = ioport__read8(data) & 0x3f; > + kvm__irq_line(kvm, dev->irq, dev->ier?1:0); > break; > case UART_LCR: > dev->lcr = ioport__read8(data); Applied, thanks! Ingo, does this fix the occasional slowdowns you are seeing? -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
