Am 03.08.2016 um 07:06 hat Stefan Weil geschrieben:
> Am 03.08.2016 um 00:05 schrieb John Snow:
> > ATA8-APT defines the state transitions for both a host controller and
> > for the hardware device during the lifecycle of a DMA transfer, in
> > section 9.7 "DMA command protocol."
> >
> > One of the interesting tidbits here is that when a device transitions
> > from DDMA0 ("Prepare state") to DDMA1 ("Data_Transfer State"), it can
> > choose to set either BSY or DRQ to signal this transition, but not both.
> >
> > as ide_sector_dma_start is the last point in our preparation process
> > before we begin the real data transfer process (for either AHCI or BMDMA),
> > this is the correct transition point for DDMA0 to DDMA1.
> >
> > I have chosen !BSY && DRQ for QEMU to make the transition from DDMA0 the
> > most obvious.
> >
> > Reported-by: Benjamin David Lunt <f...@fysnet.net>
> > Signed-off-by: John Snow <js...@redhat.com>
> > ---
> > hw/ide/core.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/hw/ide/core.c b/hw/ide/core.c
> > index d117b7c..e961d42 100644
> > --- a/hw/ide/core.c
> > +++ b/hw/ide/core.c
> > @@ -907,7 +907,7 @@ eot:
> >
> > static void ide_sector_start_dma(IDEState *s, enum ide_dma_cmd dma_cmd)
> > {
> > - s->status = READY_STAT | SEEK_STAT | DRQ_STAT | BUSY_STAT;
> > + s->status = READY_STAT | SEEK_STAT | DRQ_STAT;
> > s->io_buffer_size = 0;
> > s->dma_cmd = dma_cmd;
>
>
> This patch fixes the reported test case, thank you.
>
> Tested-by: Stefan Weil <s...@weilnetz.de>Reviewed-by: Kevin Wolf <kw...@redhat.com> Benjamin, you'll still want to fix your driver code. If John had chosen BSY && !DRQ, which is an equally valid option, qemu would be working correctly, but your test case would still hang. Kevin
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