Re: [Qemu-devel] [PATCH] pcnet: make subsystem vendor id match hardware

[Stefan Weil <weil@mail.berlios.de>]

Michael S. Tsirkin schrieb:
> Real pcnet device (AT2450) apparently has subsystem
> device and vendor id set to 0, this is out of spec
> (which requires that vendor id is obtained from PCI SIG)
> but windows xp driver seems to need this in order
> to associate.
>
> qemu sets pci subsystem id to qumranet/qemu
> since d350d97d196a632b6c7493acf07a061017fc6f7d,
> debian does not yet have this patch.
>
> https://bugzilla.redhat.com/show_bug.cgi?id=521247
>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Cc: Anthony Liguori <aliguori@us.ibm.com>
> ---
>  hw/pcnet.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/hw/pcnet.c b/hw/pcnet.c
> index 44b5b31..12260be 100644
> --- a/hw/pcnet.c
> +++ b/hw/pcnet.c
> @@ -1997,6 +1997,9 @@ static int pci_pcnet_init(PCIDevice *pci_dev)
>      pci_set_long(pci_conf + PCI_BASE_ADDRESS_0 + 4,
>                   PCI_BASE_ADDRESS_SPACE_MEMORY);
>  
> +    pci_set_word(pci_conf + PCI_SUBSYSTEM_VENDOR_ID, 0x0);
> +    pci_set_word(pci_conf + PCI_SUBSYSTEM_ID, 0x0);
> +
>      /* TODO: value must be 0 at RST# */
>      pci_conf[PCI_INTERRUPT_PIN] = 1; // interrupt pin 0
>      pci_conf[PCI_MIN_GNT] = 0x06;
>   

Don't you think that a comment in the code
(with the same explanation which you wrote above)
would be helpful in this special case?

Of course one can always call git blame, but
a comment is easier to read.

Regards
Stefan