[Qemu-devel] Re: [PATCH 2/2] pci: don't overwrite pci header type.

[Isaku Yamahata]

On Tue, Jun 15, 2010 at 12:12:07PM +0300, Michael S. Tsirkin wrote:
> On Tue, Jun 15, 2010 at 02:06:46PM +0900, Isaku Yamahata wrote:
> > Don't overwrite pci header type.
> > Otherwise, multi function bit which pci_init_header_type() sets
> > appropriately is lost.
> > Anyway PCI_HEADER_TYPE_NORMAL is zero, so it is unnecessary to zero
> > which is already zero cleared.
> > 
> > Signed-off-by: Isaku Yamahata <address@hidden>
> 
> ...
> 
> > diff --git a/hw/apb_pci.c b/hw/apb_pci.c
> > index 31c8d70..cdf3bc2 100644
> > --- a/hw/apb_pci.c
> > +++ b/hw/apb_pci.c
> > @@ -428,7 +428,8 @@ static int pbm_pci_host_init(PCIDevice *d)
> >                   PCI_STATUS_DEVSEL_MEDIUM);
> >      pci_config_set_class(d->config, PCI_CLASS_BRIDGE_HOST);
> >      pci_set_byte(d->config + PCI_HEADER_TYPE,
> > -                 PCI_HEADER_TYPE_NORMAL);
> > +                 (pci_get_byte(d->config + PCI_HEADER_TYPE) &
> > +                  PCI_HEADER_TYPE_MULTI_FUNCTION) | 
> > PCI_HEADER_TYPE_NORMAL);
> 
> what is this doing?

It changes the header type to normal device(bit 1-7) without overwriting
multi function bit(bit 8).

Apb host bridge specifies PCI_HEADER_TYPE_BRIDGE in PCIDeviceInfo,
on the other hand pbc_pci_host_init() sets the register
to PCI_HEADER_TYPE_NORMAL.
To be honest I don't know why it does so, but that is what Blue wants.
So I touch only multi function bit(bit 8) and leave other bit (bit 1-7)
unchanged.

If you don't like this hunk, I'll drop this hunk and leave it to Blue.
What do you think?


static PCIDeviceInfo pbm_pci_host_info = {
    .qdev.name = "pbm",
    .qdev.size = sizeof(PCIDevice),
    .init      = pbm_pci_host_init,
    .header_type  = PCI_HEADER_TYPE_BRIDGE,     <<<<< Here
};

-- 
yamahata